Rank Subject category Frequency Centrality
1 ENVIRONMENTAL SCIENCES & ECOLOGY 1413 0.08
2 WATER RESOURCES 1135 0.13
3 ENVIRONMENTAL SCIENCES 1029 0.28
4 GEOLOGY 847 0.03
5 GEOSCIENCES, MULTIDISCIPLINARY 807 0.21
6 MARINE & FRESHWATER BIOLOGY 606 0.12
7 ECOLOGY 600 0.19
8 ENGINEERING 409 0.13
9 LIMNOLOGY 280 0.03
10 PHYSICAL GEOGRAPHY 252 0.19
11 GEOGRAPHY, PHYSICAL 252 0
12 ENGINEERING, CIVIL 216 0
13 AGRICULTURE 153 0.12
14 ENGINEERING, ENVIRONMENTAL 144 0.09
15 BIODIVERSITY & CONSERVATION 111 0.24