Classification
577 - Ecology
157
581 - Specific topics in natural history
17
630 - Agriculture & related technologies
14
333 - Economics of land & energy
11
570 - Life sciences; biology
10
910 - Geography & travel
10
550 - Earth sciences
8
580 - Plants (Botany)
8
634 - Orchards, fruits & forestry
5
571 - Physiology & related subjects
3
579 - Microorganisms, fungi & algae
3
591 - Specific topics in natural history
3
551 - Geology, hydrology & meteorology
2
363 - Other social problems & services
1
578 - Natural history of organisms
1
590 - Animals (Zoology)
1
616 - Diseases
1
624 - Civil engineering
1