| 1 | Pollution | 2,642 | 131.2K | 3 | 8 |
| 2 | environmental pollution | 1,906 | 80.9K | 3 | 4 |
| 3 | Environmental Health | 1,212 | 77.1K | 15 | 19 |
| 4 | Ecology | 1,292 | 74.9K | 68 | 92 |
| 5 | Geophysics | 1,081 | 71.2K | 66 | 30 |
| 6 | Meteorology | 975 | 63.5K | 17 | 14 |
| 7 | Environmental Engineering | 788 | 50.5K | 16 | 20 |
| 8 | Atmospheric Physics | 750 | 48.8K | 12 | 14 |
| 9 | Biology | 235 | 41.7K | 989 | 551 |
| 10 | Climatology | 518 | 40.5K | 17 | 11 |
| 11 | Environment | 497 | 40.1K | 118 | 109 |
| 12 | sanitation | 532 | 39.4K | 11 | 15 |
| 13 | Atmospheric Chemistry | 575 | 37.6K | 10 | 13 |
| 14 | Toxicology | 846 | 36.7K | 31 | 24 |
| 15 | Science | 295 | 34.5K | 882 | 641 |
| 16 | Physics | 106 | 31.8K | 1944 | 735 |
| 17 | Environmental pollutants | 673 | 29.8K | 3 | 3 |
| 18 | Environmental monitoring | 660 | 27.4K | 6 | 11 |
| 19 | pollutants | 605 | 27.2K | 3 | 3 |
| 20 | Environmental Chemistry | 593 | 26.0K | 3 | 13 |
| 21 | Hydrology | 614 | 24.3K | 8 | 16 |
| 22 | Earth Sciences | 117 | 24.3K | 342 | 38 |
| 23 | Planets | 287 | 20.6K | 90 | 60 |
| 24 | Natural history | 184 | 20.6K | 301 | 543 |
| 25 | Birds | 748 | 20.1K | 1 | 1 |
| 26 | Oceanography | 365 | 16.9K | 50 | 56 |
| 27 | Environmental Toxicology | 316 | 15.8K | 13 | 26 |
| 28 | Water pollution | 342 | 14.7K | 27 | 52 |
| 29 | environmental protection | 227 | 14.4K | 60 | 27 |
| 30 | Chemistry | 98 | 13.8K | 2123 | 1002 |
| 31 | Marine Biology | 285 | 11.8K | 87 | 84 |
| 32 | Zoology | 345 | 10.9K | 40 | 41 |
| 33 | Biodiversity conservation | 155 | 10.0K | 60 | 124 |
| 34 | atmospheric models | 204 | 9.7K | 12 | 22 |
| 35 | California | 232 | 9.7K | 3 | 1 |
| 36 | Ornithology | 405 | 9.4K | 2 | 4 |
| 37 | atmosphere | 227 | 9.3K | 5 | 2 |
| 38 | Water | 187 | 9.1K | 99 | 158 |
| 39 | Great Lakes | 287 | 8.5K | 3 | 3 |
| 40 | Biogeochemistry | 66 | 8.3K | 125 | 44 |
| 41 | Climate change | 70 | 7.9K | 98 | 121 |
| 41 | Eutrophication | 70 | 7.9K | 95 | 121 |
| 43 | Medicine | 166 | 7.6K | 1414 | 1262 |
| 44 | Environmental Policy | 128 | 7.5K | 183 | 204 |
| 45 | Biodiversity | 145 | 7.1K | 88 | 102 |
| 46 | Geochemistry | 64 | 7.1K | 413 | 203 |
| 47 | Research | 156 | 7.0K | 1135 | 928 |
| 48 | Microbiology | 96 | 6.3K | 1210 | 945 |
| 49 | Marine Pollution | 128 | 6.1K | 16 | 23 |
| 50 | ecosystem | 151 | 5.9K | 12 | 50 |
| 51 | Wildlife conservation | 133 | 5.9K | 31 | 54 |
| 52 | Cosmochemistry | 39 | 5.7K | 115 | 20 |
| 53 | Environmental Law | 75 | 5.5K | 49 | 55 |
| 54 | Agricultural Ecology | 111 | 5.1K | 40 | 62 |
| 55 | Molecular Biology | 52 | 5.1K | 2294 | 1432 |
| 56 | Environmental Management | 147 | 4.9K | 85 | 184 |
| 57 | Analytical Chemistry | 156 | 4.8K | 504 | 524 |
| 58 | Microbial Ecology | 82 | 4.8K | 295 | 332 |
| 59 | Molecular ecology | 35 | 4.3K | 225 | 133 |
| 60 | Organic Geochemistry | 2 | 4.0K | 474 | 19 |
| 61 | Population Genetics | 47 | 3.9K | 197 | 134 |
| 62 | Molecular Genetics | 30 | 3.9K | 507 | 233 |
| 62 | Technology | 73 | 3.9K | 658 | 350 |
| 64 | Animal ecology | 91 | 3.9K | 87 | 92 |
| 65 | water supply | 59 | 3.8K | 120 | 97 |
| 66 | Aquatic ecology | 152 | 3.7K | 4 | 7 |
| 67 | Agriculture | 60 | 3.6K | 303 | 158 |
| 68 | biological evolution | 31 | 3.5K | 589 | 387 |
| 69 | Geology | 84 | 3.5K | 593 | 439 |
| 70 | environmental exposure | 83 | 3.3K | 89 | 84 |
| 71 | Conservation Biology | 77 | 3.2K | 64 | 95 |
| 72 | Parasitology | 56 | 3.1K | 414 | 198 |
| 73 | Evolution | 33 | 3.1K | 489 | 340 |
| 74 | Hydrometeorology | 56 | 2.9K | 9 | 19 |
| 75 | Botany | 104 | 2.9K | 671 | 829 |
| 76 | toxicity testing | 62 | 2.8K | 15 | 17 |
| 77 | Water quality management | 123 | 2.8K | 55 | 80 |
| 78 | Wildlife management | 140 | 2.8K | 6 | 14 |
| 79 | Fisheries | 104 | 2.8K | 111 | 147 |
| 80 | Environmental risk assessment | 75 | 2.7K | 1 | 9 |
| 81 | Pharmacology | 86 | 2.7K | 1040 | 1032 |
| 82 | environmental control | 69 | 2.6K | 1 | 9 |
| 83 | Parasitic Diseases | 33 | 2.6K | 465 | 218 |
| 84 | cryosphere | 56 | 2.6K | 35 | 45 |
| 85 | Biochemistry | 49 | 2.6K | 2839 | 2181 |
| 86 | Ecosystem management | 108 | 2.5K | 6 | 44 |
| 87 | Biogeochemical cycles | 24 | 2.3K | 95 | 82 |
| 88 | biological monitoring | 68 | 2.1K | 6 | 12 |
| 89 | polar regions | 95 | 2.1K | 22 | 27 |
| 90 | Waste management | 84 | 2.1K | 49 | 52 |
| 91 | freshwater biology | 52 | 2.1K | 61 | 73 |
| 92 | Parasites | 25 | 2.1K | 416 | 127 |
| 93 | Water Purification | 72 | 1.9K | 44 | 49 |
| 94 | Mass Spectrometry | 36 | 1.9K | 220 | 137 |
| 95 | global environmental change | 23 | 1.7K | 153 | 136 |
| 96 | Data Mining | 17 | 1.7K | 444 | 249 |
| 96 | data collection | 17 | 1.7K | 229 | 174 |
| 98 | Landscape Ecology | 31 | 1.7K | 40 | 46 |
| 99 | geological modeling | 45 | 1.6K | 25 | 48 |
| 100 | Geochemical Modeling | 44 | 1.6K | 23 | 48 |
| 101 | Epidemiology | 21 | 1.6K | 1398 | 759 |
| 102 | Geography | 49 | 1.6K | 448 | 397 |
| 103 | Hydraulic Engineering | 48 | 1.6K | 182 | 146 |
| 104 | Restoration Ecology | 18 | 1.6K | 75 | 28 |
| 105 | Forest Management | 42 | 1.5K | 153 | 171 |
| 106 | Geobiology | 28 | 1.5K | 60 | 27 |
| 107 | Forest Ecology | 41 | 1.5K | 163 | 186 |
| 108 | Risk assessment | 37 | 1.5K | 17 | 10 |
| 109 | ecological risk assessment | 34 | 1.4K | 6 | 5 |
| 109 | Health Risk Assessment | 34 | 1.4K | 12 | 7 |
| 111 | Animal Behavior | 42 | 1.4K | 435 | 509 |
| 112 | weather | 20 | 1.4K | 72 | 28 |
| 113 | Algal blooms | 10 | 1.3K | 96 | 51 |
| 113 | Cyanobacteria | 10 | 1.3K | 96 | 51 |
| 113 | microalgae | 10 | 1.3K | 96 | 51 |
| 116 | Analytical Biochemistry | 21 | 1.3K | 497 | 252 |
| 117 | Ethology | 36 | 1.3K | 367 | 456 |
| 118 | Soil Science | 36 | 1.3K | 388 | 410 |
| 119 | Climate | 23 | 1.2K | 67 | 63 |
| 120 | Biogeography | 23 | 1.2K | 261 | 302 |
| 121 | Invertebrates | 42 | 1.2K | 44 | 47 |
| 122 | Public Health | 22 | 1.1K | 2136 | 1570 |
| 123 | Paleoclimatology | 8 | 1.1K | 664 | 281 |
| 124 | Water Conservation | 48 | 1.1K | 2 | 1 |
| 125 | Scandinavia | 41 | 1.0K | 69 | 109 |
| 126 | Genetics | 22 | 1.0K | 1458 | 1560 |
| 127 | Groundwater | 29 | 1.0K | 125 | 89 |
| 128 | Spectrum analysis | 27 | 1.0K | 1552 | 1329 |
| 129 | Meteorites | 15 | 989 | 441 | 409 |
| 130 | Entomology | 40 | 988 | 580 | 481 |
| 131 | Marine mammals | 18 | 957 | 51 | 29 |
| 132 | Wetland ecology | 26 | 938 | 39 | 37 |
| 133 | Aerosols | 21 | 937 | 146 | 112 |
| 134 | Radioisotopes | 19 | 934 | 350 | 96 |
| 135 | Plant Ecology | 31 | 932 | 454 | 610 |
| 136 | Algae | 16 | 930 | 273 | 173 |
| 137 | Remote Sensing | 53 | 924 | 129 | 157 |
| 138 | food contamination | 44 | 922 | 71 | 76 |
| 138 | Isotopes | 17 | 922 | 4 | 1 |
| 140 | environmental indicators | 30 | 912 | 115 | 213 |
| 141 | Agricultural Chemistry | 49 | 907 | 404 | 656 |
| 142 | bioclimatology | 20 | 899 | 160 | 112 |
| 143 | Radiation | 22 | 898 | 698 | 415 |
| 144 | chemical spills | 24 | 872 | 1 | 1 |
| 145 | Aquatic ecosystems | 59 | 869 | 4 | 4 |
| 146 | Fish diseases | 25 | 839 | 11 | 12 |
| 146 | Aquatic animals | 25 | 839 | 11 | 8 |
| 148 | disease vectors | 7 | 838 | 621 | 186 |
| 149 | Endocrinology | 19 | 831 | 1231 | 1247 |
| 150 | United States | 43 | 815 | 1195 | 1431 |
| 151 | weather forecasting | 34 | 791 | 20 | 28 |
| 152 | Hypertension | 2 | 745 | 1800 | 796 |
| 152 | Cardiovascular system | 2 | 745 | 1791 | 819 |
| 154 | natural disasters | 26 | 731 | 231 | 303 |
| 155 | Chromatography | 30 | 721 | 339 | 332 |
| 156 | Marine Ecology | 37 | 716 | 96 | 129 |
| 157 | Ocean Engineering | 10 | 705 | 920 | 518 |
| 158 | Health | 10 | 704 | 1125 | 615 |
| 159 | Wetland conservation | 22 | 703 | 39 | 46 |
| 159 | Wetlands | 22 | 703 | 39 | 46 |
| 161 | Marine Meteorology | 28 | 698 | 86 | 145 |
| 162 | Computational Biology | 12 | 695 | 1465 | 990 |
| 163 | air | 13 | 685 | 44 | 59 |
| 164 | Hydrogeology | 9 | 681 | 385 | 123 |
| 164 | Tourism | 8 | 681 | 936 | 545 |
| 166 | air quality management | 19 | 678 | 60 | 86 |
| 167 | Climate Change Mitigation | 5 | 624 | 12 | 15 |
| 167 | Global warming | 5 | 624 | 48 | 15 |
| 167 | sea level | 5 | 624 | 12 | 15 |
| 170 | Nanotechnology | 9 | 609 | 3094 | 2314 |
| 171 | Chromatographic analysis | 25 | 594 | 539 | 478 |
| 172 | Environmental forensics | 18 | 593 | 4 | 2 |
| 173 | Pesticides | 37 | 590 | 62 | 100 |
| 174 | Seaweed | 12 | 580 | 230 | 201 |
| 175 | China | 24 | 570 | 921 | 829 |
| 176 | Civil Engineering | 30 | 566 | 460 | 324 |
| 177 | Virulence | 5 | 551 | 857 | 710 |
| 178 | mammals | 27 | 540 | 206 | 265 |
| 179 | Coastal zone management | 15 | 532 | 164 | 130 |
| 180 | Biotechnology | 15 | 511 | 3148 | 3279 |
| 181 | forestry | 24 | 510 | 43 | 58 |
| 182 | Marine resources | 10 | 499 | 251 | 145 |
| 183 | Environmental Microbiology | 10 | 495 | 698 | 726 |
| 184 | Physiology | 13 | 493 | 2155 | 1955 |
| 185 | Host-parasite interactions | 4 | 483 | 1036 | 833 |
| 185 | Immunity | 4 | 483 | 1679 | 1360 |
| 187 | Biomass Energy | 7 | 478 | 1721 | 1334 |
| 188 | Virology | 5 | 474 | 2427 | 2001 |
| 189 | Freshwater invertebrates | 18 | 467 | 26 | 65 |
| 190 | radiative transfer | 8 | 463 | 303 | 150 |
| 191 | hazard mitigation | 18 | 447 | 185 | 280 |
| 191 | environmental issues | 6 | 447 | 230 | 103 |
| 193 | Chemical Engineering | 18 | 425 | 2154 | 2478 |
| 194 | Paleoecology | 5 | 418 | 806 | 477 |
| 194 | Paleogeography | 5 | 418 | 709 | 448 |
| 196 | Electrophoresis | 19 | 408 | 555 | 694 |
| 197 | Zoonoses | 2 | 403 | 393 | 72 |
| 198 | Engineering | 26 | 402 | 1570 | 1713 |
| 198 | soil pollution | 22 | 402 | 43 | 94 |
| 200 | Fishery management | 21 | 397 | 210 | 254 |
| 201 | Nuclear Chemistry | 24 | 396 | 301 | 294 |
| 202 | Geomorphology | 11 | 384 | 718 | 764 |
| 203 | Energy Policy | 11 | 376 | 1407 | 1682 |
| 203 | food technology | 13 | 376 | 1208 | 1289 |
| 203 | soil conservation | 18 | 376 | 150 | 262 |
| 206 | Natural resources | 9 | 370 | 372 | 351 |
| 207 | Radiochemistry | 20 | 369 | 306 | 265 |
| 208 | Ecological Engineering | 6 | 357 | 384 | 280 |
| 209 | Hydrodynamics | 8 | 355 | 340 | 275 |
| 210 | Bioremediation | 7 | 341 | 410 | 312 |
| 211 | Horticulture | 3 | 339 | 848 | 222 |
| 211 | animals | 16 | 339 | 447 | 412 |
| 213 | Steroids | 3 | 336 | 978 | 462 |
| 214 | Ecological Genetics | 22 | 335 | 96 | 150 |
| 215 | Pesticide residues | 7 | 332 | 19 | 26 |
| 215 | Food additives | 7 | 332 | 721 | 623 |
| 217 | Anthropology | 4 | 330 | 1354 | 568 |
| 218 | Environmental Geology | 14 | 328 | 692 | 859 |
| 219 | Stochastic Processes | 10 | 327 | 423 | 238 |
| 220 | air quality | 9 | 325 | 30 | 36 |
| 221 | Genomics | 20 | 323 | 1223 | 1908 |
| 222 | Carbon | 4 | 322 | 1155 | 932 |
| 223 | Hormones | 1 | 321 | 2006 | 750 |
| 223 | Social behavior | 10 | 321 | 571 | 591 |
| 225 | Surface Chemistry | 6 | 320 | 2765 | 2152 |
| 225 | Colloids | 6 | 320 | 2664 | 2224 |
| 227 | Human evolution | 2 | 315 | 492 | 255 |
| 228 | rivers | 16 | 306 | 45 | 105 |
| 229 | Molecular evolution | 6 | 304 | 1029 | 945 |
| 230 | Geodesy | 6 | 303 | 489 | 246 |
| 231 | Phylogeny | 5 | 301 | 697 | 583 |
| 232 | Australia | 3 | 299 | 1979 | 710 |
| 233 | Astrophysics | 6 | 292 | 2220 | 1737 |
| 234 | soil microbiology | 7 | 278 | 941 | 1183 |
| 235 | Biomedical Engineering | 6 | 262 | 3962 | 3271 |
| 236 | Structure-activity relationship | 6 | 257 | 215 | 174 |
| 237 | Cell Biology | 2 | 256 | 4512 | 3209 |
| 238 | Urban Policy | 9 | 255 | 341 | 395 |
| 238 | urban forestry | 9 | 255 | 50 | 74 |
| 240 | Cytology | 2 | 254 | 4696 | 3221 |
| 241 | Breeding | 1 | 253 | 1852 | 717 |
| 242 | Transport | 14 | 252 | 190 | 348 |
| 242 | Sea | 14 | 252 | 156 | 283 |
| 242 | Fishery resources | 14 | 252 | 190 | 311 |
| 242 | government | 7 | 252 | 388 | 262 |
| 246 | coal | 12 | 251 | 759 | 1183 |
| 247 | Photochemistry | 5 | 242 | 1415 | 998 |
| 248 | biological invasions | 5 | 239 | 433 | 354 |
| 249 | Ecohydrology | 14 | 236 | 47 | 133 |
| 249 | Food | 3 | 236 | 3167 | 2121 |
| 251 | wetland management | 4 | 235 | 101 | 54 |
| 252 | Plant physiology | 7 | 230 | 1396 | 1575 |
| 253 | Bacteriology | 5 | 227 | 1481 | 1511 |
| 254 | Photobiology | 3 | 224 | 1480 | 809 |
| 255 | energy resources | 10 | 222 | 667 | 1281 |
| 256 | Plant Pathology | 2 | 218 | 220 | 72 |
| 257 | Biochemical Engineering | 5 | 217 | 2603 | 2977 |
| 258 | Reproduction | 4 | 214 | 2017 | 1453 |
| 259 | Glaciology | 17 | 211 | 47 | 124 |
| 259 | glaciers | 17 | 211 | 40 | 121 |
| 261 | radioactive waste | 4 | 204 | 667 | 812 |
| 261 | Hazardous waste | 4 | 204 | 802 | 879 |
| 263 | plankton | 8 | 200 | 80 | 106 |
| 264 | soil management | 5 | 199 | 378 | 407 |
| 265 | bats | 8 | 196 | 37 | 26 |
| 266 | tillage | 3 | 193 | 385 | 350 |
| 267 | emergency management | 5 | 192 | 593 | 457 |
| 268 | Infections | 2 | 189 | 1425 | 1010 |
| 268 | infection | 2 | 189 | 2033 | 1259 |
| 268 | Continental shelf | 8 | 189 | 200 | 280 |
| 271 | Agronomy | 5 | 188 | 402 | 487 |
| 271 | wildlife diseases | 9 | 188 | 32 | 31 |
| 273 | occupational diseases | 3 | 185 | 876 | 599 |
| 274 | Sociology | 4 | 182 | 2709 | 1829 |
| 275 | Nanomedicine | 3 | 181 | 193 | 147 |
| 275 | Plant diseases | 7 | 181 | 1314 | 1245 |
| 275 | nanoscience | 3 | 181 | 2853 | 2291 |
| 278 | Proteomics | 10 | 180 | 546 | 944 |
| 278 | Sustainable agriculture | 1 | 180 | 1320 | 466 |
| 280 | Risk Management | 3 | 178 | 706 | 399 |
| 281 | mutation | 4 | 174 | 534 | 524 |
| 281 | Fracture mechanics | 2 | 174 | 1638 | 919 |
| 283 | Fertilizers | 4 | 165 | 285 | 241 |
| 284 | water resources | 7 | 164 | 200 | 177 |
| 285 | Epigenetics | 3 | 162 | 216 | 86 |
| 285 | Epigenomics | 3 | 162 | 213 | 85 |
| 287 | Sustainable Development | 4 | 161 | 1867 | 1636 |
| 288 | Pediatrics | 2 | 157 | 2837 | 2022 |
| 289 | Agricultural Science | 9 | 156 | 90 | 244 |
| 290 | Chemical Ecology | 3 | 154 | 519 | 455 |
| 290 | pheromones | 3 | 154 | 469 | 424 |
| 292 | Membranes | 2 | 152 | 1946 | 1585 |
| 293 | Statistics | 9 | 151 | 1636 | 1555 |
| 293 | Reservoirs | 10 | 151 | 47 | 59 |
| 295 | Fluid Mechanics | 4 | 150 | 1509 | 1121 |
| 296 | Aquaculture | 6 | 149 | 992 | 1022 |
| 297 | city planning | 3 | 145 | 1626 | 1075 |
| 298 | Archaeology | 9 | 144 | 759 | 792 |
| 298 | Atmospheric Science | 9 | 144 | 66 | 135 |
| 300 | Mathematics | 4 | 140 | 4959 | 3308 |
| 301 | Water chemistry | 3 | 139 | 293 | 141 |
| 302 | transgenic organisms | 5 | 138 | 163 | 252 |
| 303 | Comparative Physiology | 6 | 137 | 538 | 657 |
| 304 | Emerging infectious diseases | 3 | 136 | 338 | 279 |
| 305 | Biophysics | 8 | 133 | 3860 | 4742 |
| 306 | Social Sciences | 8 | 132 | 2361 | 2054 |
| 307 | Municipal Engineering | 10 | 131 | 76 | 228 |
| 308 | Transportation | 5 | 128 | 1242 | 1291 |
| 308 | Quality of life | 2 | 128 | 1858 | 1415 |
| 310 | Neurology | 5 | 127 | 4159 | 4564 |
| 310 | Flood forecasting | 1 | 127 | 238 | 52 |
| 310 | Water Microbiology | 5 | 127 | 280 | 361 |
| 310 | Flood control | 1 | 127 | 560 | 102 |
| 310 | Chemical analysis | 3 | 127 | 1219 | 983 |
| 315 | Immunology | 3 | 126 | 3757 | 3545 |
| 316 | Developing countries | 5 | 125 | 1827 | 1785 |
| 317 | Embryology | 2 | 124 | 1735 | 1540 |
| 318 | Neurotoxicology | 3 | 123 | 560 | 531 |
| 318 | Soil biology | 4 | 123 | 781 | 1046 |
| 318 | North America | 28 | 123 | 139 | 504 |
| 321 | Astronomy | 5 | 122 | 2130 | 2266 |
| 322 | mycoses | 1 | 121 | 1381 | 1011 |
| 322 | Bacterial infections | 1 | 121 | 1494 | 1040 |
| 324 | Cancer | 4 | 120 | 3185 | 3463 |
| 325 | plant communities | 4 | 115 | 956 | 1152 |
| 326 | Quality Control | 7 | 113 | 1147 | 1553 |
| 326 | drug toxicity | 4 | 113 | 323 | 398 |
| 328 | Numerical Analysis | 3 | 112 | 2314 | 1561 |
| 328 | Ethnoarchaeology | 2 | 112 | 213 | 152 |
| 328 | aerosol | 7 | 112 | 214 | 321 |
| 331 | Genetically modified organisms | 3 | 109 | 15 | 18 |
| 331 | safety | 3 | 109 | 58 | 43 |
| 333 | Transportation Engineering | 1 | 108 | 844 | 378 |
| 334 | Product life cycle | 3 | 106 | 299 | 344 |
| 334 | green products | 3 | 106 | 268 | 337 |
| 336 | Physical Geography | 12 | 105 | 187 | 404 |
| 336 | Mycology | 7 | 105 | 1099 | 1494 |
| 338 | Chromosomes | 3 | 102 | 1006 | 1046 |
| 338 | industrial waste | 4 | 102 | 694 | 1205 |
| 340 | Wind power | 9 | 101 | 92 | 210 |
| 340 | particles | 2 | 101 | 1273 | 832 |
| 342 | Watershed management | 4 | 100 | 134 | 101 |
| 343 | Environmental Geochemistry | 6 | 98 | 246 | 431 |
| 344 | Cartography | 3 | 96 | 539 | 232 |
| 344 | Developmental Biology | 3 | 96 | 1954 | 2211 |
| 346 | Genetic Toxicology | 3 | 94 | 483 | 624 |
| 347 | Food Microbiology | 3 | 93 | 1230 | 1530 |
| 347 | Lipids | 3 | 93 | 1341 | 1514 |
| 349 | Engineering Geology | 3 | 92 | 1447 | 1394 |
| 350 | Optics | 14 | 91 | 2638 | 3273 |
| 350 | Animal migration | 6 | 91 | 1 | 1 |
| 352 | Biochemical Genetics | 1 | 88 | 896 | 215 |
| 352 | greenhouse effect | 3 | 88 | 44 | 69 |
| 352 | Carbon dioxide | 3 | 88 | 44 | 69 |
| 355 | Human Geography | 5 | 87 | 838 | 857 |
| 356 | Materials | 3 | 86 | 5397 | 5027 |
| 356 | Insects | 4 | 86 | 1328 | 1239 |
| 358 | environmental remediation | 4 | 85 | 248 | 331 |
| 358 | ecotourism | 2 | 85 | 293 | 253 |
| 360 | natural products | 3 | 84 | 1851 | 1603 |
| 360 | Genetic markers | 3 | 84 | 249 | 215 |
| 360 | biological factors | 3 | 84 | 2018 | 1929 |
| 360 | biochemical markers | 3 | 84 | 908 | 808 |
| 364 | Materials Science | 5 | 83 | 3734 | 4185 |
| 364 | Paleontology | 4 | 83 | 1151 | 1089 |
| 364 | Regional Planning | 3 | 83 | 1527 | 1320 |
| 364 | Japan | 1 | 83 | 3272 | 1615 |
| 368 | Neuropsychology | 2 | 80 | 2585 | 2276 |
| 368 | Neurophysiology | 2 | 80 | 3123 | 2993 |
| 368 | Brain | 2 | 80 | 2897 | 2711 |
| 371 | winds | 6 | 79 | 39 | 56 |
| 371 | Plants | 10 | 79 | 1187 | 2191 |
| 373 | Nanoparticles | 2 | 78 | 2167 | 1986 |
| 373 | herbicides | 1 | 78 | 490 | 273 |
| 373 | miniaturization | 2 | 78 | 2176 | 2167 |
| 376 | Biocompatible Materials | 1 | 76 | 4848 | 4121 |
| 376 | ozone | 1 | 76 | 282 | 96 |
| 378 | Psychophysiology | 3 | 69 | 2539 | 3006 |
| 379 | Landslides | 2 | 68 | 319 | 422 |
| 380 | Technology Assessment | 3 | 67 | 308 | 580 |
| 380 | Primary health care | 1 | 67 | 2935 | 1824 |
| 380 | Cost effectiveness | 3 | 67 | 69 | 87 |
| 380 | Decision making | 3 | 67 | 1548 | 1543 |
| 380 | Radiation effects | 4 | 67 | 507 | 869 |
| 385 | sustainability | 2 | 66 | 1124 | 1241 |
| 386 | Systems Biology | 3 | 65 | 1614 | 1884 |
| 387 | Chemical industry | 5 | 64 | 1092 | 1251 |
| 388 | peer review | 2 | 61 | 93 | 60 |
| 388 | scholarly publishing | 2 | 61 | 172 | 121 |
| 390 | Geographic information systems | 7 | 60 | 679 | 1054 |
| 390 | human behavior | 2 | 60 | 2842 | 3368 |
| 390 | Behavior | 2 | 60 | 3581 | 3954 |
| 390 | sexual behavior | 2 | 60 | 836 | 799 |
| 394 | Industrial Microbiology | 4 | 59 | 1764 | 2652 |
| 395 | System analysis | 5 | 57 | 2020 | 2580 |
| 396 | Physical Chemistry | 4 | 55 | 2023 | 2500 |
| 396 | Computational Complexity | 1 | 55 | 1800 | 968 |
| 398 | Paleopathology | 4 | 54 | 259 | 285 |
| 398 | Foodborne diseases | 2 | 54 | 325 | 358 |
| 400 | Solar Energy | 3 | 53 | 1726 | 2313 |
| 401 | Research Design | 3 | 52 | 1193 | 1560 |
| 401 | Measurement | 3 | 52 | 1373 | 1558 |
| 401 | standardization | 3 | 52 | 50 | 68 |
| 404 | Probability | 2 | 51 | 728 | 741 |
| 404 | Financial management | 2 | 51 | 623 | 778 |
| 404 | Risk | 2 | 51 | 690 | 768 |
| 407 | Greenhouse gases | 3 | 50 | 343 | 609 |
| 407 | forest policy | 2 | 50 | 449 | 489 |
| 409 | Geotechnical Engineering | 2 | 49 | 849 | 816 |
| 409 | Soil Mechanics | 2 | 49 | 1384 | 1383 |
| 409 | Evolutionary Genetics | 2 | 49 | 907 | 1020 |
| 409 | Molecular Epidemiology | 2 | 49 | 907 | 1020 |
| 413 | Renewable Energy Sources | 2 | 46 | 3106 | 3922 |
| 413 | Visual Perception | 3 | 46 | 1620 | 2173 |
| 413 | lakes | 2 | 46 | 89 | 72 |
| 413 | Memory | 3 | 46 | 1747 | 2416 |
| 413 | Attention | 3 | 46 | 1679 | 2277 |
| 413 | Minerals | 2 | 46 | 1010 | 1076 |
| 413 | Perception | 3 | 46 | 1772 | 2339 |
| 420 | Telecommunication | 1 | 45 | 3893 | 2868 |
| 420 | Antarctica | 1 | 45 | 905 | 573 |
| 422 | Mineralogy | 1 | 44 | 2015 | 1542 |
| 422 | Clinical Immunology | 1 | 44 | 1974 | 1795 |
| 422 | Industrial Safety | 1 | 44 | 2007 | 1476 |
| 422 | Chemical Oceanography | 3 | 44 | 289 | 520 |
| 422 | ports | 3 | 44 | 276 | 391 |
| 422 | Waterways | 3 | 44 | 187 | 221 |
| 422 | Harbors | 3 | 44 | 207 | 236 |
| 422 | Ore deposits | 1 | 44 | 791 | 697 |
| 430 | Hospitality industry | 1 | 43 | 761 | 600 |
| 430 | Agricultural systems | 2 | 43 | 394 | 643 |
| 432 | Rural Development | 2 | 41 | 715 | 741 |
| 432 | community development | 2 | 41 | 706 | 750 |
| 432 | Fire ecology | 2 | 41 | 72 | 153 |
| 432 | Ultrasonics | 1 | 41 | 1937 | 1931 |
| 432 | Sonochemistry | 1 | 41 | 1051 | 1262 |
| 432 | DNA | 5 | 41 | 429 | 902 |
| 438 | Periglacial processes | 2 | 40 | 165 | 249 |
| 438 | Permafrost | 2 | 40 | 165 | 249 |
| 438 | Frozen ground | 2 | 40 | 167 | 249 |
| 441 | Systems Theory | 3 | 39 | 633 | 556 |
| 441 | Biological Systems | 3 | 39 | 823 | 1048 |
| 443 | structural stability | 2 | 38 | 583 | 673 |
| 443 | Raman spectroscopy | 1 | 38 | 1363 | 1183 |
| 445 | Underwater Archaeology | 5 | 37 | 65 | 75 |
| 445 | Roads | 3 | 37 | 738 | 771 |
| 445 | animal diseases | 5 | 37 | 345 | 778 |
| 448 | Mechanical Engineering | 2 | 36 | 2921 | 2557 |
| 448 | Catalysis | 1 | 36 | 4176 | 4002 |
| 448 | Solar power plants | 1 | 36 | 396 | 451 |
| 448 | Herpetology | 5 | 36 | 235 | 371 |
| 448 | Photovoltaic Cells | 1 | 36 | 398 | 452 |
| 448 | scientific research | 4 | 36 | 40 | 67 |
| 448 | solar cells | 1 | 36 | 1456 | 1597 |
| 448 | Reptiles | 5 | 36 | 229 | 337 |
| 448 | enzymes | 1 | 36 | 2339 | 2301 |
| 448 | Leisure | 3 | 36 | 361 | 528 |
| 458 | Outdoor recreation | 1 | 35 | 158 | 162 |
| 458 | Liquid chromatography | 3 | 35 | 527 | 552 |
| 460 | Engineering Mathematics | 1 | 34 | 3612 | 2627 |
| 460 | Polymers | 1 | 34 | 5557 | 4943 |
| 460 | Bioacoustics | 4 | 34 | 61 | 146 |
| 460 | management | 1 | 34 | 4827 | 4071 |
| 460 | Atomic spectroscopy | 3 | 34 | 1167 | 1459 |
| 465 | Clinical Chemistry | 3 | 33 | 2980 | 4198 |
| 465 | energy conservation | 2 | 33 | 2495 | 3320 |
| 465 | Molecular Spectroscopy | 1 | 33 | 2585 | 2417 |
| 465 | Population | 2 | 33 | 1271 | 1460 |
| 465 | Recycling | 1 | 33 | 1025 | 1401 |
| 470 | Bioengineering | 1 | 32 | 6148 | 6107 |
| 470 | Biosensors | 1 | 32 | 1990 | 2434 |
| 470 | Bioelectronics | 1 | 32 | 1754 | 2225 |
| 473 | Sustainable Engineering | 4 | 31 | 1469 | 2488 |
| 473 | Fisheries Law | 2 | 31 | 168 | 262 |
| 473 | fisheries management | 2 | 31 | 168 | 262 |
| 476 | Mining Engineering | 1 | 30 | 1019 | 781 |
| 476 | shellfish | 2 | 30 | 217 | 257 |
| 476 | Mountains | 12 | 30 | 81 | 541 |
| 479 | Plant genetic engineering | 2 | 29 | 1140 | 1581 |
| 479 | transgenic animals | 2 | 29 | 350 | 616 |
| 479 | Transgenic plants | 2 | 29 | 620 | 1022 |
| 482 | Radiology | 2 | 28 | 1788 | 1889 |
| 483 | History | 16 | 27 | 480 | 574 |
| 483 | Plant tissue culture | 1 | 27 | 1190 | 1271 |
| 483 | Microscopy | 2 | 27 | 2016 | 2079 |
| 483 | Plant cell culture | 1 | 27 | 1096 | 1256 |
| 483 | venom | 2 | 27 | 955 | 1328 |
| 483 | Toxins | 2 | 27 | 1066 | 1454 |
| 489 | Sedimentology | 4 | 26 | 534 | 1087 |
| 490 | Environmental Ethics | 2 | 25 | 209 | 205 |
| 490 | Zeolites | 1 | 25 | 1450 | 1693 |
| 492 | Computational Fluid Dynamics | 2 | 24 | 831 | 1072 |
| 493 | Tropical Medicine | 2 | 23 | 2288 | 2924 |
| 493 | gene mapping | 1 | 23 | 3109 | 3633 |
| 493 | DNA polymerases | 1 | 23 | 735 | 1202 |
| 496 | Computer Science | 1 | 22 | 3507 | 2934 |
| 496 | Photography | 11 | 22 | 1392 | 1565 |
| 496 | Solar System | 1 | 22 | 1133 | 1165 |
| 499 | Radiobiology | 1 | 21 | 2125 | 2289 |
| 500 | Petroleum Engineering | 8 | 20 | 442 | 1323 |
| 500 | Public Policy | 3 | 20 | 1754 | 3153 |
| 500 | Microbial Biotechnology | 2 | 20 | 1304 | 2022 |
| 500 | Soil fertility | 1 | 20 | 586 | 830 |
| 500 | Soil ecology | 1 | 20 | 1228 | 1551 |
| 505 | Medical Laboratory Science | 1 | 19 | 3539 | 4155 |
| 505 | Fluid Dynamics | 3 | 19 | 1176 | 1828 |
| 505 | Environmental Education | 2 | 19 | 466 | 688 |
| 505 | Estuaries | 1 | 19 | 250 | 367 |
| 505 | South America | 2 | 19 | 152 | 128 |
| 510 | Systems Analysis | 2 | 18 | 1378 | 1938 |
| 510 | Ichthyology | 3 | 18 | 493 | 778 |
| 510 | Ocean-atmosphere interaction | 1 | 18 | 193 | 140 |
| 510 | Light | 2 | 18 | 1125 | 1813 |
| 510 | Fish | 3 | 18 | 370 | 660 |
| 515 | Industrial Engineering | 3 | 17 | 1996 | 3112 |
| 515 | Respiratory Infections | 1 | 17 | 678 | 801 |
| 515 | Biometrics | 5 | 17 | 838 | 1645 |
| 515 | drainage | 2 | 17 | 510 | 630 |
| 515 | Fungi | 1 | 17 | 1585 | 1849 |
| 515 | Mollusks | 1 | 17 | 480 | 401 |
| 515 | Influenza | 1 | 17 | 539 | 674 |
| 522 | Neural circuitry | 1 | 16 | 2843 | 3320 |
| 522 | Nervous system | 1 | 16 | 3576 | 4274 |
| 522 | Sedimentary rocks | 1 | 16 | 933 | 1106 |
| 525 | Phytochemistry | 2 | 15 | 411 | 834 |
| 525 | Biodegradation | 1 | 15 | 1347 | 1794 |
| 525 | Phytoremediation | 2 | 15 | 411 | 834 |
| 525 | Bioreactors | 2 | 15 | 411 | 834 |
| 525 | Europe | 3 | 15 | 3289 | 4878 |
| 525 | Fouling | 1 | 15 | 492 | 759 |
| 531 | Economic Development | 1 | 14 | 2708 | 2990 |
| 531 | Organometallic chemistry | 1 | 14 | 2680 | 2817 |
| 531 | Helminthology | 2 | 14 | 192 | 278 |
| 531 | Phylogenetics | 1 | 14 | 232 | 281 |
| 531 | Organometallic compounds | 1 | 14 | 1814 | 2029 |
| 531 | Helminths | 2 | 14 | 192 | 278 |
| 531 | Amphibians | 4 | 14 | 231 | 476 |
| 538 | Freshwater Ecology | 2 | 13 | 377 | 592 |
| 538 | Biotelemetry | 3 | 13 | 66 | 214 |
| 538 | Nanostructured Materials | 1 | 13 | 4038 | 4608 |
| 538 | Nanostructures | 1 | 13 | 3342 | 3761 |
| 538 | International Finance | 1 | 13 | 2222 | 2472 |
| 538 | Solutions | 1 | 13 | 692 | 737 |
| 538 | Petroleum | 6 | 13 | 198 | 566 |
| 538 | Sites | 1 | 13 | 872 | 1243 |
| 538 | natural gas | 6 | 13 | 256 | 949 |
| 547 | Nutrition | 1 | 12 | 6231 | 7335 |
| 547 | Food Policy | 1 | 12 | 608 | 926 |
| 547 | Nutrition physiology | 1 | 12 | 1319 | 1701 |
| 547 | Latin America | 1 | 12 | 2006 | 1601 |
| 547 | world | 1 | 12 | 1203 | 1787 |
| 552 | Green Chemistry | 2 | 11 | 1975 | 3095 |
| 552 | Mathematical Physics | 1 | 11 | 3802 | 3644 |
| 552 | Image Processing | 2 | 11 | 2637 | 3746 |
| 552 | Erosion | 2 | 11 | 101 | 444 |
| 552 | Statistical physics | 1 | 11 | 4469 | 4789 |
| 557 | Metallography | 2 | 10 | 1040 | 1717 |
| 557 | Asia | 3 | 10 | 3036 | 4792 |
| 559 | Global Health | 1 | 9 | 1993 | 2575 |
| 559 | health services accessibility | 1 | 9 | 1590 | 2196 |
| 559 | X-ray spectroscopy | 4 | 9 | 168 | 551 |
| 559 | Fluorescence | 1 | 9 | 895 | 1099 |
| 563 | Economic History | 2 | 8 | 4195 | 5054 |
| 563 | Water quality | 1 | 8 | 511 | 879 |
| 563 | Korea | 2 | 8 | 477 | 773 |
| 563 | Ethnology | 3 | 8 | 1504 | 2536 |
| 563 | Genes | 2 | 8 | 1469 | 2560 |
| 568 | Electrical Engineering | 4 | 7 | 3303 | 5032 |
| 568 | Molecular Pharmacology | 1 | 7 | 1286 | 1929 |
| 568 | Cytogenetics | 1 | 7 | 2363 | 3259 |
| 568 | Freeze-Drying | 1 | 7 | 727 | 1061 |
| 568 | Reproductive toxicology | 2 | 7 | 562 | 1279 |
| 568 | Hypothermia | 1 | 7 | 727 | 1061 |
| 568 | Freeze Drying | 1 | 7 | 727 | 1061 |
| 568 | clay | 1 | 7 | 1322 | 1929 |
| 568 | clay minerals | 1 | 7 | 511 | 803 |
| 568 | Marine sediments | 1 | 7 | 57 | 56 |
| 578 | Signal Processing | 1 | 6 | 3531 | 4463 |
| 578 | Marine invertebrates | 1 | 6 | 472 | 626 |
| 578 | economic policy | 3 | 6 | 2492 | 3905 |
| 578 | indoor air pollution | 1 | 6 | 773 | 1245 |
| 578 | Africa | 1 | 6 | 2790 | 3221 |
| 578 | Ventilation | 1 | 6 | 1006 | 1484 |
| 578 | Sick building syndrome | 1 | 6 | 773 | 1245 |
| 585 | Imaging systems | 1 | 5 | 1512 | 1872 |
| 586 | Nursing | 1 | 4 | 2926 | 3830 |
| 586 | Electronics | 1 | 4 | 5178 | 6100 |
| 586 | Asthma | 1 | 4 | 1206 | 1835 |
| 586 | Genetic engineering | 1 | 4 | 3345 | 4665 |
| 586 | Radiation Protection | 1 | 4 | 1192 | 1472 |
| 586 | History of Nursing | 1 | 4 | 66 | 57 |
| 586 | Synthetic biology | 1 | 4 | 592 | 945 |
| 586 | Entropy | 1 | 4 | 1974 | 2558 |
| 586 | civilization | 4 | 4 | 1172 | 1503 |
| 586 | plant viruses | 2 | 4 | 273 | 670 |
| 586 | Allergy | 1 | 4 | 1749 | 2565 |
| 586 | energy development | 1 | 4 | 1676 | 2534 |
| 586 | Allergies | 1 | 4 | 310 | 622 |
| 599 | Computer Graphics | 1 | 3 | 2597 | 3556 |
| 599 | Organic Chemistry | 3 | 3 | 3086 | 5216 |
| 599 | Marine Biotechnology | 1 | 3 | 443 | 847 |
| 599 | industrial hygiene | 2 | 3 | 1436 | 2774 |
| 599 | Social policy | 2 | 3 | 1292 | 2387 |
| 599 | international trade | 1 | 3 | 1232 | 1740 |
| 599 | International Business | 1 | 3 | 392 | 764 |
| 599 | viruses | 1 | 3 | 2165 | 3226 |
| 599 | commerce | 1 | 3 | 2545 | 3242 |
| 599 | Geospatial data | 1 | 3 | 65 | 249 |
| 599 | disaster relief | 1 | 3 | 456 | 896 |
| 599 | Eigenvalues | 1 | 3 | 424 | 384 |
| 611 | Economics | 1 | 2 | 5430 | 6421 |
| 611 | Information Systems | 1 | 2 | 2465 | 3742 |
| 611 | Neurobiology | 1 | 2 | 2477 | 3671 |
| 611 | Social History | 5 | 2 | 401 | 1004 |
| 611 | occupational health and safety | 1 | 2 | 392 | 661 |
| 611 | Carcinogenesis | 1 | 2 | 1627 | 2589 |
| 611 | Environmental carcinogens | 1 | 2 | 62 | 169 |
| 611 | Developmental Neurobiology | 1 | 2 | 965 | 1449 |
| 611 | Magnetic Resonance Spectroscopy | 1 | 2 | 1719 | 2416 |
| 611 | nuclear magnetic resonance spectroscopy | 1 | 2 | 1151 | 1636 |
| 611 | Documentation | 1 | 2 | 595 | 878 |
| 611 | England | 1 | 2 | 355 | 332 |
| 611 | NMR | 1 | 2 | 898 | 1346 |
| 611 | planning | 1 | 2 | 1304 | 2133 |
| 611 | investigative techniques | 1 | 2 | 302 | 686 |
| 611 | Economic planning | 1 | 2 | 872 | 1465 |
| 611 | magnetic resonance | 1 | 2 | 927 | 1391 |
| 628 | Game Theory | 1 | 1 | 931 | 1360 |
| 628 | Surveying | 3 | 1 | 174 | 666 |
| 628 | Nuclear Energy | 1 | 1 | 1790 | 2438 |
| 628 | Human genetics | 1 | 1 | 3096 | 4598 |
| 628 | Occupational Health | 1 | 1 | 1923 | 3027 |
| 628 | Bryology | 1 | 1 | 377 | 562 |
| 628 | Demography | 1 | 1 | 1196 | 1898 |
| 628 | Medical Microbiology | 1 | 1 | 3408 | 5133 |
| 628 | Public Administration | 1 | 1 | 2165 | 3000 |
| 628 | Environmental Economics | 1 | 1 | 805 | 1445 |
| 628 | History of Medicine | 3 | 1 | 505 | 936 |
| 628 | Photogrammetry | 1 | 1 | 1497 | 1989 |
| 628 | Regional Development | 1 | 1 | 463 | 810 |
| 628 | sustainable forestry | 1 | 1 | 270 | 609 |
| 628 | bryophytes | 1 | 1 | 221 | 350 |
| 628 | Library Science | 1 | 1 | 2142 | 2762 |
| 628 | Paleoanthropology | 1 | 1 | 18 | 49 |
| 628 | libraries | 1 | 1 | 1344 | 1595 |
| 628 | Sociobiology | 1 | 1 | 507 | 843 |
| 628 | scientific societies | 1 | 1 | 1306 | 2283 |
| 628 | social aspects | 1 | 1 | 151 | 313 |
| 628 | Endocrine system | 1 | 1 | 1245 | 1215 |
| 628 | synthesis | 1 | 1 | 1701 | 2414 |
| 628 | Human biology | 1 | 1 | 1111 | 1832 |
| 628 | international cooperation | 2 | 1 | 764 | 1823 |
| 628 | eugenics | 1 | 1 | 1028 | 1825 |
| 628 | Birth control | 1 | 1 | 875 | 1565 |
| 655 | Literature | 1 | 0 | 1444 | 1427 |
| 655 | Planetary Science | 2 | 0 | 654 | 1435 |
| 655 | Animal Biotechnology | 1 | 0 | 354 | 764 |
| 655 | Landscape Architecture | 1 | 0 | 358 | 685 |
| 655 | Dance | 1 | 0 | 491 | 704 |
| 655 | Animal breeding | 1 | 0 | 1219 | 1934 |
| 655 | Open source software | 1 | 0 | 192 | 375 |
| 655 | Simulation Methods | 1 | 0 | 1745 | 2748 |
| 655 | Folklore | 2 | 0 | 171 | 318 |
| 655 | Art | 3 | 0 | 468 | 883 |
| 655 | Bioinformatics | 1 | 0 | 3315 | 4815 |
| 655 | Geodynamics | 1 | 0 | 1228 | 1810 |
| 655 | gardens | 1 | 0 | 78 | 155 |
| 655 | India | 1 | 0 | 2793 | 4051 |
| 655 | recreation | 1 | 0 | 1045 | 1726 |
