| 1 | Pollution | 1,707 | 94.5K | 13 | 16 |
| 2 | environmental pollution | 1,284 | 59.5K | 11 | 13 |
| 3 | Environmental Health | 753 | 57.3K | 78 | 38 |
| 4 | Geophysics | 588 | 49.3K | 188 | 78 |
| 5 | Ecology | 697 | 44.2K | 211 | 216 |
| 6 | Meteorology | 600 | 40.8K | 55 | 46 |
| 7 | Environmental Engineering | 494 | 36.4K | 58 | 37 |
| 8 | Atmospheric Physics | 414 | 35.2K | 51 | 31 |
| 9 | sanitation | 314 | 28.9K | 27 | 29 |
| 10 | Toxicology | 596 | 28.3K | 78 | 53 |
| 11 | Environment | 281 | 28.0K | 300 | 206 |
| 12 | Atmospheric Chemistry | 330 | 27.1K | 34 | 29 |
| 13 | Science | 150 | 25.2K | 1954 | 1056 |
| 14 | Environmental pollutants | 489 | 23.4K | 7 | 4 |
| 15 | Climatology | 258 | 23.1K | 78 | 45 |
| 16 | Environmental monitoring | 483 | 21.6K | 30 | 36 |
| 17 | Biology | 88 | 20.6K | 2639 | 1200 |
| 18 | pollutants | 414 | 20.4K | 7 | 5 |
| 19 | Hydrology | 419 | 20.3K | 34 | 26 |
| 20 | Environmental Chemistry | 409 | 19.1K | 7 | 31 |
| 21 | Physics | 47 | 17.2K | 3918 | 1471 |
| 22 | Natural history | 100 | 17.1K | 613 | 801 |
| 23 | Environmental Toxicology | 244 | 13.9K | 33 | 39 |
| 24 | Planets | 143 | 12.6K | 228 | 119 |
| 25 | Water pollution | 244 | 12.2K | 66 | 84 |
| 26 | environmental protection | 128 | 10.3K | 212 | 80 |
| 27 | Oceanography | 219 | 9.8K | 126 | 129 |
| 28 | Marine Biology | 171 | 7.8K | 210 | 169 |
| 29 | Water | 137 | 7.6K | 178 | 214 |
| 30 | Earth Sciences | 35 | 7.0K | 1081 | 257 |
| 31 | Geochemistry | 49 | 6.8K | 589 | 229 |
| 32 | Great Lakes | 183 | 6.5K | 10 | 6 |
| 33 | Biogeochemistry | 39 | 6.4K | 275 | 83 |
| 34 | atmosphere | 148 | 5.7K | 14 | 8 |
| 35 | Medicine | 96 | 5.7K | 2711 | 2125 |
| 36 | Microbiology | 81 | 5.6K | 1714 | 1350 |
| 37 | Birds | 291 | 5.5K | 23 | 28 |
| 38 | Cosmochemistry | 26 | 5.4K | 203 | 19 |
| 39 | Biodiversity conservation | 54 | 5.3K | 322 | 298 |
| 40 | Research | 91 | 5.1K | 2220 | 1535 |
| 41 | Zoology | 148 | 4.9K | 202 | 158 |
| 42 | ecosystem | 101 | 4.7K | 54 | 89 |
| 43 | Environmental Policy | 74 | 4.6K | 444 | 372 |
| 44 | Microbial Ecology | 57 | 4.5K | 458 | 395 |
| 45 | Marine Pollution | 67 | 4.4K | 69 | 42 |
| 46 | Climate change | 23 | 4.4K | 377 | 277 |
| 46 | Eutrophication | 23 | 4.4K | 368 | 276 |
| 48 | Analytical Chemistry | 127 | 4.0K | 680 | 672 |
| 49 | Organic Geochemistry | 2 | 4.0K | 568 | 20 |
| 50 | Environmental Management | 76 | 3.7K | 319 | 308 |
| 51 | atmospheric models | 65 | 3.3K | 92 | 114 |
| 52 | toxicity testing | 66 | 3.2K | 29 | 26 |
| 53 | Agricultural Ecology | 71 | 3.2K | 63 | 109 |
| 54 | Environmental Law | 43 | 3.1K | 141 | 135 |
| 55 | Ornithology | 155 | 3.1K | 29 | 40 |
| 56 | Biodiversity | 55 | 3.1K | 376 | 318 |
| 57 | Aquatic ecology | 100 | 3.1K | 24 | 18 |
| 58 | Technology | 44 | 3.0K | 1151 | 502 |
| 59 | water supply | 32 | 3.0K | 241 | 150 |
| 60 | environmental exposure | 56 | 2.7K | 209 | 134 |
| 61 | Geology | 50 | 2.6K | 952 | 606 |
| 62 | Hydrometeorology | 38 | 2.5K | 22 | 32 |
| 63 | biological evolution | 16 | 2.5K | 1051 | 586 |
| 64 | Parasitology | 34 | 2.5K | 739 | 286 |
| 65 | Water quality management | 101 | 2.4K | 82 | 100 |
| 66 | Pharmacology | 62 | 2.4K | 1604 | 1427 |
| 67 | Environmental risk assessment | 52 | 2.3K | 7 | 9 |
| 68 | environmental control | 46 | 2.2K | 8 | 9 |
| 69 | Wildlife conservation | 44 | 2.2K | 210 | 216 |
| 70 | Molecular Biology | 24 | 2.1K | 4325 | 3125 |
| 71 | Parasitic Diseases | 20 | 2.0K | 890 | 363 |
| 72 | Chemistry | 55 | 2.0K | 3544 | 3665 |
| 73 | Evolution | 14 | 1.9K | 1027 | 567 |
| 74 | Agriculture | 29 | 1.9K | 685 | 347 |
| 75 | Botany | 56 | 1.9K | 1156 | 1265 |
| 76 | Fisheries | 56 | 1.8K | 277 | 271 |
| 77 | Waste management | 70 | 1.8K | 69 | 67 |
| 78 | Ecosystem management | 76 | 1.8K | 21 | 72 |
| 79 | Animal ecology | 31 | 1.8K | 338 | 228 |
| 80 | Mass Spectrometry | 29 | 1.6K | 347 | 194 |
| 81 | Water Purification | 59 | 1.6K | 65 | 61 |
| 82 | Biogeochemical cycles | 10 | 1.6K | 262 | 164 |
| 83 | Parasites | 15 | 1.6K | 751 | 210 |
| 84 | Wildlife management | 54 | 1.5K | 77 | 55 |
| 85 | freshwater biology | 31 | 1.5K | 161 | 128 |
| 86 | Biochemistry | 34 | 1.5K | 4254 | 3637 |
| 87 | Molecular ecology | 13 | 1.5K | 610 | 401 |
| 88 | Epidemiology | 18 | 1.4K | 2063 | 1141 |
| 89 | Hydraulic Engineering | 37 | 1.4K | 161 | 122 |
| 90 | biological monitoring | 44 | 1.4K | 15 | 33 |
| 91 | California | 53 | 1.3K | 44 | 51 |
| 92 | Conservation Biology | 16 | 1.3K | 476 | 305 |
| 93 | Geography | 38 | 1.3K | 621 | 513 |
| 94 | Risk assessment | 33 | 1.3K | 27 | 14 |
| 95 | Molecular Genetics | 13 | 1.3K | 1217 | 680 |
| 96 | ecological risk assessment | 32 | 1.2K | 8 | 5 |
| 96 | Health Risk Assessment | 32 | 1.2K | 16 | 8 |
| 98 | Invertebrates | 40 | 1.2K | 60 | 62 |
| 99 | Climate | 20 | 1.1K | 116 | 95 |
| 100 | Geobiology | 11 | 1.1K | 221 | 60 |
| 101 | Population Genetics | 13 | 1.1K | 671 | 476 |
| 102 | polar regions | 37 | 1.0K | 106 | 96 |
| 103 | Soil Science | 26 | 1.0K | 586 | 536 |
| 104 | cryosphere | 10 | 1.0K | 232 | 138 |
| 105 | Groundwater | 24 | 965 | 164 | 106 |
| 106 | Public Health | 14 | 957 | 3685 | 2334 |
| 107 | Meteorites | 13 | 953 | 587 | 509 |
| 108 | Algae | 15 | 914 | 348 | 208 |
| 109 | Paleoclimatology | 2 | 907 | 1453 | 378 |
| 110 | Radioisotopes | 15 | 902 | 540 | 117 |
| 111 | bioclimatology | 19 | 891 | 213 | 145 |
| 112 | Isotopes | 13 | 890 | 10 | 1 |
| 113 | Agricultural Chemistry | 47 | 881 | 524 | 795 |
| 114 | chemical spills | 23 | 866 | 1 | 2 |
| 115 | Aerosols | 16 | 851 | 218 | 139 |
| 116 | food contamination | 40 | 834 | 102 | 104 |
| 117 | Fish diseases | 24 | 815 | 20 | 20 |
| 117 | Aquatic animals | 24 | 815 | 22 | 15 |
| 119 | Forest Ecology | 22 | 805 | 346 | 365 |
| 119 | Forest Management | 22 | 805 | 331 | 335 |
| 121 | Landscape Ecology | 13 | 792 | 161 | 131 |
| 122 | Endocrinology | 14 | 791 | 2014 | 1801 |
| 123 | Water Conservation | 27 | 763 | 3 | 3 |
| 124 | Entomology | 21 | 758 | 1067 | 659 |
| 125 | Aquatic ecosystems | 40 | 748 | 10 | 7 |
| 126 | Hypertension | 2 | 745 | 2493 | 1110 |
| 126 | Cardiovascular system | 2 | 745 | 2443 | 1148 |
| 128 | Chromatography | 28 | 713 | 431 | 395 |
| 129 | Wetland ecology | 13 | 687 | 132 | 80 |
| 130 | air | 13 | 685 | 70 | 77 |
| 131 | Health | 5 | 643 | 2335 | 874 |
| 132 | Genetics | 7 | 629 | 3650 | 2724 |
| 133 | Biogeography | 9 | 616 | 643 | 628 |
| 134 | United States | 25 | 613 | 2242 | 2164 |
| 135 | Chromatographic analysis | 23 | 586 | 651 | 553 |
| 136 | Plant Ecology | 12 | 581 | 1028 | 965 |
| 137 | weather | 10 | 576 | 239 | 129 |
| 138 | Seaweed | 11 | 566 | 298 | 247 |
| 139 | Environmental forensics | 15 | 560 | 5 | 2 |
| 140 | Nanotechnology | 7 | 545 | 4184 | 3000 |
| 141 | air quality management | 13 | 521 | 130 | 138 |
| 142 | Pesticides | 34 | 517 | 76 | 125 |
| 143 | Analytical Biochemistry | 8 | 504 | 1290 | 739 |
| 144 | weather forecasting | 19 | 496 | 52 | 71 |
| 145 | Wetland conservation | 11 | 487 | 108 | 92 |
| 145 | Wetlands | 11 | 487 | 110 | 92 |
| 147 | Computational Biology | 5 | 478 | 3056 | 1588 |
| 148 | Biotechnology | 14 | 477 | 3962 | 4160 |
| 149 | Biomass Energy | 7 | 476 | 1980 | 1505 |
| 150 | Environmental Microbiology | 7 | 471 | 1028 | 906 |
| 150 | environmental indicators | 10 | 471 | 573 | 515 |
| 152 | Civil Engineering | 23 | 468 | 506 | 268 |
| 153 | Coastal zone management | 10 | 459 | 310 | 192 |
| 154 | Radiation | 15 | 458 | 1140 | 868 |
| 154 | Virulence | 3 | 458 | 1491 | 1058 |
| 156 | Hydrogeology | 4 | 453 | 690 | 185 |
| 157 | China | 16 | 452 | 1382 | 1100 |
| 158 | disease vectors | 2 | 446 | 1460 | 401 |
| 159 | Virology | 5 | 437 | 3208 | 2834 |
| 160 | global environmental change | 7 | 436 | 604 | 554 |
| 161 | Marine resources | 7 | 430 | 429 | 207 |
| 162 | Marine Ecology | 14 | 422 | 329 | 259 |
| 163 | Animal Behavior | 14 | 412 | 1024 | 1339 |
| 164 | natural disasters | 16 | 410 | 423 | 579 |
| 165 | Electrophoresis | 17 | 400 | 715 | 810 |
| 166 | Algal blooms | 4 | 398 | 273 | 188 |
| 166 | Cyanobacteria | 4 | 398 | 273 | 188 |
| 166 | microalgae | 4 | 398 | 273 | 188 |
| 169 | Geochemical Modeling | 10 | 381 | 149 | 173 |
| 169 | geological modeling | 10 | 381 | 216 | 201 |
| 171 | Zoonoses | 1 | 379 | 734 | 99 |
| 172 | environmental issues | 4 | 378 | 391 | 155 |
| 173 | food technology | 13 | 375 | 1407 | 1530 |
| 174 | soil pollution | 17 | 363 | 91 | 136 |
| 175 | Ethology | 12 | 353 | 872 | 1248 |
| 176 | Marine Meteorology | 17 | 345 | 169 | 244 |
| 176 | Host-parasite interactions | 2 | 345 | 1942 | 1325 |
| 176 | Immunity | 2 | 345 | 2899 | 2081 |
| 179 | Horticulture | 3 | 337 | 928 | 254 |
| 179 | soil conservation | 13 | 337 | 265 | 346 |
| 181 | Steroids | 2 | 335 | 1545 | 599 |
| 182 | Energy Policy | 9 | 333 | 1736 | 2007 |
| 183 | Ecological Engineering | 5 | 326 | 538 | 356 |
| 183 | Scandinavia | 11 | 326 | 249 | 213 |
| 185 | Freshwater invertebrates | 13 | 325 | 59 | 132 |
| 186 | Hormones | 1 | 320 | 2605 | 985 |
| 187 | Nuclear Chemistry | 21 | 318 | 419 | 414 |
| 188 | Pesticide residues | 6 | 317 | 22 | 33 |
| 188 | Food additives | 6 | 317 | 949 | 780 |
| 190 | Anthropology | 2 | 315 | 2479 | 714 |
| 190 | Human evolution | 2 | 315 | 615 | 316 |
| 192 | Surface Chemistry | 5 | 313 | 3560 | 2599 |
| 192 | Colloids | 5 | 313 | 3471 | 2708 |
| 194 | Engineering | 24 | 310 | 1787 | 2108 |
| 194 | Geomorphology | 6 | 310 | 1146 | 966 |
| 196 | Remote Sensing | 18 | 304 | 517 | 512 |
| 197 | Natural resources | 9 | 301 | 435 | 471 |
| 198 | Chemical Engineering | 12 | 292 | 3013 | 3368 |
| 199 | Radiochemistry | 17 | 291 | 426 | 382 |
| 199 | animals | 10 | 291 | 740 | 532 |
| 201 | Spectrum analysis | 15 | 290 | 2708 | 3049 |
| 202 | Paleoecology | 1 | 286 | 1754 | 704 |
| 202 | Hydrodynamics | 8 | 286 | 360 | 349 |
| 202 | Paleogeography | 1 | 286 | 1567 | 648 |
| 205 | Australia | 2 | 283 | 3056 | 905 |
| 206 | Cytology | 3 | 280 | 5228 | 4055 |
| 207 | Environmental Geology | 9 | 278 | 966 | 947 |
| 208 | hazard mitigation | 12 | 266 | 336 | 485 |
| 209 | Structure-activity relationship | 6 | 257 | 253 | 220 |
| 210 | Cell Biology | 2 | 255 | 5763 | 4180 |
| 211 | Breeding | 1 | 253 | 2282 | 854 |
| 212 | Photochemistry | 5 | 242 | 1714 | 1192 |
| 213 | soil microbiology | 5 | 239 | 1336 | 1527 |
| 214 | Molecular evolution | 4 | 236 | 1889 | 1457 |
| 214 | Phylogeny | 4 | 236 | 911 | 806 |
| 216 | Carbon | 1 | 234 | 2396 | 1257 |
| 217 | Biomedical Engineering | 5 | 229 | 5125 | 3974 |
| 217 | Plant physiology | 7 | 229 | 1664 | 1908 |
| 219 | Bacteriology | 5 | 227 | 1954 | 1971 |
| 220 | Photobiology | 3 | 224 | 1699 | 904 |
| 220 | Food | 2 | 224 | 4497 | 2567 |
| 220 | biological invasions | 3 | 224 | 749 | 431 |
| 223 | Fishery management | 11 | 222 | 461 | 507 |
| 224 | Physiology | 6 | 221 | 4068 | 3777 |
| 225 | Astrophysics | 5 | 220 | 3053 | 2539 |
| 226 | Urban Policy | 7 | 217 | 480 | 527 |
| 226 | urban forestry | 7 | 217 | 92 | 114 |
| 228 | Reproduction | 4 | 214 | 2642 | 1900 |
| 229 | rivers | 8 | 209 | 145 | 164 |
| 230 | government | 3 | 207 | 905 | 349 |
| 231 | Geodesy | 3 | 205 | 907 | 406 |
| 232 | radioactive waste | 4 | 202 | 723 | 882 |
| 232 | Hazardous waste | 4 | 202 | 882 | 960 |
| 234 | wetland management | 2 | 200 | 275 | 79 |
| 235 | Bioremediation | 6 | 187 | 540 | 605 |
| 236 | occupational diseases | 3 | 185 | 1202 | 786 |
| 237 | Agronomy | 3 | 183 | 627 | 549 |
| 238 | Nanomedicine | 3 | 180 | 238 | 180 |
| 238 | nanoscience | 3 | 180 | 3426 | 2813 |
| 238 | energy resources | 8 | 180 | 900 | 1661 |
| 241 | Sustainable agriculture | 1 | 179 | 1584 | 555 |
| 242 | Genomics | 7 | 175 | 2942 | 3377 |
| 243 | Fracture mechanics | 2 | 174 | 1929 | 1050 |
| 244 | Ecohydrology | 7 | 163 | 191 | 225 |
| 245 | Epigenetics | 3 | 162 | 247 | 99 |
| 245 | Biochemical Engineering | 2 | 162 | 4549 | 4094 |
| 245 | Epigenomics | 3 | 162 | 244 | 97 |
| 248 | Numerical Analysis | 5 | 159 | 2181 | 1479 |
| 249 | Stochastic Processes | 7 | 158 | 601 | 496 |
| 249 | air quality | 4 | 158 | 162 | 101 |
| 251 | Pediatrics | 2 | 155 | 4072 | 2991 |
| 252 | Chemical Ecology | 3 | 154 | 638 | 543 |
| 252 | Glaciology | 13 | 154 | 73 | 178 |
| 252 | pheromones | 3 | 154 | 578 | 503 |
| 252 | glaciers | 13 | 154 | 66 | 170 |
| 256 | water resources | 7 | 152 | 127 | 100 |
| 256 | Membranes | 2 | 152 | 2492 | 1987 |
| 258 | Fluid Mechanics | 6 | 151 | 1483 | 1305 |
| 259 | bats | 7 | 150 | 49 | 51 |
| 260 | Plant diseases | 4 | 147 | 2072 | 1618 |
| 261 | Aquaculture | 6 | 143 | 1225 | 1271 |
| 262 | Risk Management | 2 | 142 | 1132 | 598 |
| 262 | city planning | 2 | 142 | 2301 | 1254 |
| 264 | Ocean Engineering | 1 | 141 | 2772 | 1469 |
| 264 | wildlife diseases | 5 | 141 | 90 | 56 |
| 266 | Water chemistry | 3 | 138 | 357 | 169 |
| 267 | Atmospheric Science | 7 | 136 | 117 | 180 |
| 268 | mammals | 5 | 132 | 1003 | 924 |
| 269 | Social Sciences | 3 | 130 | 4669 | 2523 |
| 269 | Sociology | 3 | 130 | 3813 | 2737 |
| 271 | Quality of life | 2 | 128 | 2375 | 1767 |
| 272 | Proteomics | 5 | 127 | 1115 | 1456 |
| 272 | Water Microbiology | 5 | 127 | 329 | 444 |
| 272 | coal | 5 | 127 | 1437 | 1837 |
| 275 | Chemical analysis | 3 | 125 | 1491 | 1206 |
| 276 | Embryology | 2 | 124 | 2289 | 2059 |
| 276 | Flood forecasting | 1 | 124 | 278 | 77 |
| 276 | Flood control | 1 | 124 | 665 | 146 |
| 276 | Fertilizers | 2 | 124 | 565 | 363 |
| 276 | aerosol | 8 | 124 | 262 | 366 |
| 281 | Astronomy | 5 | 122 | 2696 | 2889 |
| 281 | Soil biology | 4 | 122 | 935 | 1240 |
| 283 | Municipal Engineering | 9 | 121 | 99 | 268 |
| 284 | soil management | 3 | 120 | 640 | 711 |
| 284 | plankton | 5 | 120 | 155 | 208 |
| 286 | tillage | 1 | 115 | 855 | 614 |
| 287 | transgenic organisms | 4 | 114 | 209 | 325 |
| 288 | Quality Control | 7 | 113 | 1314 | 1873 |
| 288 | Infections | 1 | 113 | 2509 | 1766 |
| 288 | infection | 1 | 113 | 3434 | 2147 |
| 291 | Neurology | 3 | 110 | 6587 | 6217 |
| 292 | Genetically modified organisms | 3 | 109 | 14 | 19 |
| 292 | safety | 3 | 109 | 78 | 52 |
| 292 | Social behavior | 5 | 109 | 1043 | 1312 |
| 295 | Neurotoxicology | 2 | 108 | 901 | 736 |
| 296 | Transportation Engineering | 1 | 106 | 756 | 318 |
| 297 | Mycology | 7 | 105 | 1332 | 1848 |
| 298 | Product life cycle | 3 | 104 | 354 | 407 |
| 298 | green products | 3 | 104 | 310 | 399 |
| 300 | industrial waste | 4 | 101 | 761 | 1360 |
| 301 | particles | 2 | 100 | 1465 | 947 |
| 302 | Environmental Geochemistry | 6 | 97 | 296 | 503 |
| 302 | forestry | 6 | 97 | 171 | 247 |
| 304 | mutation | 3 | 95 | 804 | 952 |
| 305 | Sustainable Development | 2 | 94 | 3143 | 2483 |
| 305 | Continental shelf | 3 | 94 | 494 | 530 |
| 307 | Lipids | 3 | 93 | 1703 | 1955 |
| 308 | Physical Geography | 9 | 91 | 281 | 515 |
| 308 | Engineering Geology | 3 | 91 | 1618 | 1590 |
| 310 | drug toxicity | 2 | 90 | 725 | 590 |
| 311 | Human Geography | 5 | 87 | 962 | 1017 |
| 312 | Wind power | 7 | 85 | 165 | 302 |
| 313 | Genetic markers | 3 | 84 | 289 | 256 |
| 313 | biochemical markers | 3 | 84 | 1061 | 949 |
| 315 | Genetic Toxicology | 2 | 83 | 729 | 820 |
| 315 | environmental remediation | 3 | 83 | 384 | 404 |
| 315 | natural products | 3 | 83 | 2115 | 1815 |
| 315 | biological factors | 3 | 83 | 2361 | 2353 |
| 319 | Regional Planning | 2 | 81 | 2201 | 1607 |
| 320 | Transportation | 3 | 79 | 1937 | 1851 |
| 321 | Neuropsychology | 1 | 78 | 4219 | 2986 |
| 321 | Neurophysiology | 1 | 78 | 4962 | 3972 |
| 321 | Nanoparticles | 2 | 78 | 2639 | 2402 |
| 321 | Brain | 1 | 78 | 4582 | 3587 |
| 321 | herbicides | 1 | 78 | 576 | 333 |
| 321 | miniaturization | 2 | 78 | 2662 | 2721 |
| 327 | Food Microbiology | 2 | 77 | 1884 | 2101 |
| 327 | winds | 6 | 77 | 51 | 69 |
| 329 | ozone | 1 | 75 | 310 | 111 |
| 330 | Restoration Ecology | 2 | 73 | 675 | 625 |
| 330 | Tourism | 1 | 73 | 2766 | 2015 |
| 332 | Cancer | 2 | 72 | 5303 | 5278 |
| 333 | DNA | 1 | 70 | 1389 | 788 |
| 334 | Insects | 2 | 67 | 2149 | 1631 |
| 335 | Primary health care | 1 | 65 | 3823 | 2440 |
| 336 | Comparative Physiology | 3 | 64 | 989 | 1135 |
| 336 | Animal migration | 2 | 64 | 3 | 1 |
| 338 | Paleontology | 2 | 63 | 1808 | 1481 |
| 338 | Chemical industry | 5 | 63 | 1267 | 1454 |
| 340 | Industrial Microbiology | 4 | 59 | 2043 | 3212 |
| 340 | human behavior | 2 | 59 | 3702 | 4376 |
| 340 | Landslides | 1 | 59 | 531 | 480 |
| 340 | Behavior | 2 | 59 | 4739 | 5202 |
| 340 | sexual behavior | 2 | 59 | 1019 | 1013 |
| 340 | Psychophysiology | 2 | 59 | 4096 | 4243 |
| 346 | Marine mammals | 3 | 58 | 348 | 415 |
| 347 | Statistics | 6 | 57 | 2389 | 2917 |
| 347 | System analysis | 6 | 57 | 2128 | 3032 |
| 349 | Climate Change Mitigation | 1 | 56 | 116 | 207 |
| 349 | Global warming | 1 | 56 | 354 | 242 |
| 349 | sea level | 1 | 56 | 116 | 207 |
| 352 | Physical Chemistry | 4 | 55 | 2417 | 3102 |
| 353 | emergency management | 1 | 53 | 1923 | 1283 |
| 353 | plant communities | 2 | 53 | 1519 | 1876 |
| 355 | Research Design | 3 | 52 | 1634 | 2089 |
| 355 | Measurement | 3 | 52 | 1489 | 1718 |
| 355 | Developing countries | 2 | 52 | 3749 | 3367 |
| 355 | standardization | 3 | 52 | 69 | 96 |
| 359 | Solar Energy | 3 | 51 | 1992 | 2772 |
| 359 | Reservoirs | 3 | 51 | 224 | 224 |
| 361 | Mathematics | 3 | 49 | 6904 | 5960 |
| 361 | Evolutionary Genetics | 2 | 49 | 1092 | 1255 |
| 361 | Molecular Epidemiology | 2 | 49 | 1092 | 1255 |
| 364 | Geotechnical Engineering | 2 | 48 | 755 | 722 |
| 364 | Agricultural Science | 2 | 48 | 333 | 578 |
| 364 | Soil Mechanics | 2 | 48 | 1553 | 1544 |
| 367 | Ecological Genetics | 4 | 46 | 653 | 901 |
| 367 | Minerals | 2 | 46 | 1170 | 1243 |
| 369 | lakes | 2 | 45 | 120 | 92 |
| 369 | Antarctica | 1 | 45 | 1107 | 722 |
| 371 | Mineralogy | 1 | 44 | 2460 | 1878 |
| 371 | Clinical Immunology | 1 | 44 | 2604 | 2285 |
| 371 | Industrial Safety | 1 | 44 | 2552 | 1761 |
| 371 | Chemical Oceanography | 3 | 44 | 350 | 666 |
| 371 | Geographic information systems | 4 | 44 | 1113 | 1431 |
| 371 | Ore deposits | 1 | 44 | 914 | 808 |
| 377 | Telecommunication | 1 | 43 | 4175 | 2655 |
| 378 | Population | 2 | 41 | 1625 | 1672 |
| 379 | Systems Theory | 3 | 39 | 732 | 650 |
| 379 | Technology Assessment | 1 | 39 | 845 | 903 |
| 379 | Biological Systems | 3 | 39 | 893 | 1251 |
| 379 | Cost effectiveness | 1 | 39 | 189 | 126 |
| 379 | Decision making | 1 | 39 | 3214 | 2487 |
| 384 | Foodborne diseases | 1 | 38 | 630 | 578 |
| 385 | Solar power plants | 1 | 36 | 462 | 517 |
| 385 | Photovoltaic Cells | 1 | 36 | 464 | 518 |
| 385 | scientific research | 4 | 36 | 43 | 79 |
| 385 | Roads | 2 | 36 | 1058 | 917 |
| 385 | solar cells | 1 | 36 | 1730 | 1885 |
| 390 | Mechanical Engineering | 2 | 35 | 3511 | 3040 |
| 390 | Catalysis | 1 | 35 | 5104 | 4927 |
| 390 | enzymes | 1 | 35 | 2921 | 2901 |
| 390 | Liquid chromatography | 3 | 35 | 642 | 686 |
| 394 | Engineering Mathematics | 1 | 34 | 4448 | 3083 |
| 394 | Atomic spectroscopy | 3 | 34 | 1367 | 1775 |
| 396 | Optics | 11 | 33 | 3382 | 5439 |
| 396 | Paleopathology | 1 | 33 | 657 | 466 |
| 396 | Agricultural systems | 1 | 33 | 703 | 884 |
| 396 | Recycling | 1 | 33 | 1228 | 1703 |
| 400 | Mining Engineering | 1 | 30 | 1148 | 864 |
| 401 | Sustainable Engineering | 3 | 29 | 1892 | 3055 |
| 401 | Emerging infectious diseases | 1 | 29 | 777 | 943 |
| 401 | Mountains | 8 | 29 | 194 | 665 |
| 404 | radiative transfer | 2 | 27 | 869 | 968 |
| 404 | Microscopy | 2 | 27 | 2597 | 2701 |
| 406 | Sedimentology | 4 | 26 | 611 | 1319 |
| 406 | Fishery resources | 4 | 26 | 658 | 1345 |
| 406 | shellfish | 1 | 26 | 416 | 374 |
| 409 | Biophysics | 3 | 25 | 7055 | 9219 |
| 409 | Environmental Ethics | 2 | 25 | 243 | 244 |
| 409 | Clinical Chemistry | 1 | 25 | 5348 | 5577 |
| 409 | Zeolites | 1 | 25 | 1657 | 1958 |
| 413 | History | 7 | 24 | 902 | 733 |
| 413 | Computational Fluid Dynamics | 2 | 24 | 983 | 1274 |
| 415 | Transport | 3 | 23 | 752 | 1487 |
| 415 | Sea | 3 | 23 | 674 | 1288 |
| 417 | Fisheries Law | 1 | 22 | 319 | 388 |
| 417 | fisheries management | 1 | 22 | 319 | 388 |
| 417 | Solar System | 1 | 22 | 1395 | 1483 |
| 420 | Public Policy | 3 | 20 | 2260 | 4030 |
| 420 | Microbial Biotechnology | 2 | 20 | 1499 | 2366 |
| 420 | Soil fertility | 1 | 20 | 704 | 988 |
| 420 | Soil ecology | 1 | 20 | 1432 | 1825 |
| 424 | Medical Laboratory Science | 1 | 19 | 4186 | 4728 |
| 424 | Herpetology | 2 | 19 | 532 | 625 |
| 424 | Estuaries | 1 | 19 | 349 | 507 |
| 424 | Amphibians | 2 | 19 | 482 | 471 |
| 424 | South America | 2 | 19 | 197 | 158 |
| 424 | Reptiles | 2 | 19 | 548 | 583 |
| 430 | Photography | 10 | 18 | 1212 | 1612 |
| 430 | Systems Analysis | 2 | 18 | 1631 | 2306 |
| 430 | Probability | 1 | 18 | 1264 | 1456 |
| 430 | Ocean-atmosphere interaction | 1 | 18 | 220 | 159 |
| 430 | Financial management | 1 | 18 | 1111 | 1453 |
| 430 | Risk | 1 | 18 | 1230 | 1483 |
| 430 | Light | 2 | 18 | 1512 | 2417 |
| 437 | Industrial Engineering | 3 | 17 | 2290 | 3704 |
| 437 | Respiratory Infections | 1 | 17 | 862 | 1041 |
| 437 | drainage | 2 | 17 | 415 | 584 |
| 437 | Fungi | 1 | 17 | 1922 | 2305 |
| 437 | Marine sediments | 2 | 17 | 44 | 43 |
| 437 | Influenza | 1 | 17 | 709 | 917 |
| 443 | Neural circuitry | 1 | 16 | 3411 | 3993 |
| 443 | Nervous system | 1 | 16 | 4627 | 5472 |
| 443 | Sedimentary rocks | 1 | 16 | 1065 | 1308 |
| 446 | Fluid Dynamics | 2 | 15 | 1678 | 2348 |
| 446 | energy conservation | 1 | 15 | 3589 | 4423 |
| 446 | Biodegradation | 1 | 15 | 1561 | 2126 |
| 446 | Tropical Medicine | 1 | 15 | 3777 | 4156 |
| 446 | Fouling | 1 | 15 | 570 | 907 |
| 451 | Developmental Biology | 1 | 14 | 3792 | 4670 |
| 451 | Organometallic chemistry | 1 | 14 | 3301 | 3482 |
| 451 | Organometallic compounds | 1 | 14 | 2122 | 2407 |
| 454 | Petroleum Engineering | 7 | 13 | 523 | 1687 |
| 454 | Phytochemistry | 1 | 13 | 709 | 996 |
| 454 | Ichthyology | 2 | 13 | 750 | 1028 |
| 454 | Phytoremediation | 1 | 13 | 709 | 996 |
| 454 | Helminthology | 1 | 13 | 372 | 337 |
| 454 | Bioreactors | 1 | 13 | 709 | 996 |
| 454 | International Finance | 1 | 13 | 2659 | 2962 |
| 454 | Solutions | 1 | 13 | 777 | 852 |
| 454 | Helminths | 1 | 13 | 372 | 337 |
| 454 | Petroleum | 6 | 13 | 224 | 663 |
| 454 | natural gas | 6 | 13 | 280 | 1091 |
| 454 | Fish | 2 | 13 | 566 | 863 |
| 466 | Freshwater Ecology | 2 | 12 | 419 | 721 |
| 466 | Latin America | 1 | 12 | 2436 | 1917 |
| 466 | Chromosomes | 1 | 12 | 1959 | 2605 |
| 466 | Japan | 4 | 12 | 2320 | 4181 |
| 470 | Mathematical Physics | 1 | 11 | 4860 | 4525 |
| 470 | Reproductive toxicology | 7 | 11 | 320 | 1506 |
| 470 | Statistical physics | 1 | 11 | 5567 | 5957 |
| 470 | Radiation effects | 1 | 11 | 1321 | 1844 |
| 474 | Biometrics | 2 | 10 | 1641 | 2501 |
| 475 | Green Chemistry | 1 | 9 | 2823 | 3819 |
| 475 | Fluorescence | 1 | 9 | 1059 | 1297 |
| 477 | Economic History | 2 | 8 | 5131 | 6270 |
| 477 | X-ray spectroscopy | 3 | 8 | 268 | 716 |
| 477 | Water quality | 1 | 8 | 631 | 1083 |
| 480 | Radiology | 1 | 7 | 3292 | 3837 |
| 480 | clay | 1 | 7 | 1530 | 2273 |
| 480 | clay minerals | 1 | 7 | 590 | 932 |
| 483 | North America | 2 | 6 | 1449 | 2655 |
| 484 | Image Processing | 1 | 5 | 3646 | 4781 |
| 484 | Plant genetic engineering | 1 | 5 | 1777 | 2506 |
| 484 | transgenic animals | 1 | 5 | 622 | 1140 |
| 484 | economic policy | 2 | 5 | 3554 | 5015 |
| 484 | Transgenic plants | 1 | 5 | 1047 | 1699 |
| 484 | Imaging systems | 1 | 5 | 1680 | 2163 |
| 490 | Electronics | 1 | 4 | 5990 | 6927 |
| 490 | Radiation Protection | 1 | 4 | 1547 | 1938 |
| 490 | Entropy | 1 | 4 | 2199 | 3032 |
| 490 | energy development | 1 | 4 | 1920 | 2978 |
| 494 | Plant Pathology | 1 | 3 | 350 | 594 |
| 494 | international trade | 1 | 3 | 1439 | 2070 |
| 494 | France | 1 | 3 | 924 | 1023 |
| 494 | International Business | 1 | 3 | 470 | 893 |
| 494 | commerce | 1 | 3 | 2966 | 3931 |
| 494 | disaster relief | 1 | 3 | 560 | 1127 |
| 494 | Eigenvalues | 1 | 3 | 498 | 459 |
| 501 | Economics | 1 | 2 | 6737 | 8095 |
| 501 | Information Systems | 1 | 2 | 3096 | 4746 |
| 501 | occupational health and safety | 1 | 2 | 554 | 887 |
| 501 | industrial hygiene | 1 | 2 | 2614 | 3722 |
| 501 | Carcinogenesis | 1 | 2 | 2127 | 3321 |
| 501 | Environmental carcinogens | 1 | 2 | 84 | 240 |
| 501 | Social policy | 1 | 2 | 2048 | 3075 |
| 501 | civilization | 2 | 2 | 1864 | 2106 |
| 501 | Documentation | 1 | 2 | 786 | 1151 |
| 501 | Asia | 1 | 2 | 5695 | 7641 |
| 501 | animal diseases | 1 | 2 | 1044 | 1896 |
| 501 | planning | 1 | 2 | 1581 | 2666 |
| 501 | investigative techniques | 1 | 2 | 354 | 812 |
| 501 | Europe | 1 | 2 | 6532 | 8409 |
| 501 | Economic planning | 1 | 2 | 1031 | 1755 |
| 501 | venom | 1 | 2 | 1861 | 2602 |
| 501 | Toxins | 1 | 2 | 2011 | 2811 |
| 518 | Immunology | 1 | 1 | 6471 | 8470 |
| 518 | Game Theory | 1 | 1 | 1120 | 1689 |
| 518 | Surveying | 3 | 1 | 179 | 672 |
| 518 | Nuclear Energy | 1 | 1 | 2250 | 3059 |
| 518 | Organic Chemistry | 1 | 1 | 5024 | 6648 |
| 518 | Medical Microbiology | 1 | 1 | 4532 | 6624 |
| 518 | Environmental Economics | 1 | 1 | 992 | 1742 |
| 518 | Photogrammetry | 1 | 1 | 1840 | 2456 |
| 518 | Library Science | 1 | 1 | 2703 | 3533 |
| 518 | libraries | 1 | 1 | 1624 | 1959 |
| 518 | scientific societies | 1 | 1 | 1818 | 3073 |
| 518 | synthesis | 1 | 1 | 1950 | 2839 |
| 518 | international cooperation | 2 | 1 | 905 | 2307 |
| 531 | Literature | 1 | 0 | 1685 | 1687 |
| 531 | Planetary Science | 1 | 0 | 1052 | 1740 |
| 531 | Acoustics | 1 | 0 | 598 | 983 |
| 531 | Dance | 1 | 0 | 579 | 850 |
| 531 | History of Medicine | 1 | 0 | 1072 | 1423 |
| 531 | Green Technology | 2 | 0 | 686 | 2138 |
| 531 | Simulation Methods | 1 | 0 | 2078 | 3393 |
| 531 | Geodynamics | 1 | 0 | 1451 | 2190 |
| 531 | Sound | 1 | 0 | 1780 | 2688 |
| 531 | recreation | 1 | 0 | 1269 | 2142 |
