Classification
581 - Specific topics in natural history
160
580 - Plants (Botany)
127
571 - Physiology & related subjects
85
577 - Ecology
82
333 - Economics of land & energy
54
630 - Agriculture & related technologies
31
634 - Orchards, fruits & forestry
25
660 - Chemical engineering
17
578 - Natural history of organisms
16
572 - Biochemistry
14
631 - Techniques, equipment & materials
13
363 - Other social problems & services
12
579 - Microorganisms, fungi & algae
6
551 - Geology, hydrology & meteorology
4
570 - Life sciences; biology
4
576 - Genetics & evolution
4
910 - Geography & travel
4
591 - Specific topics in natural history
3
592 - Invertebrates
3
664 - Food technology
3
000 - Computer science, information & general works
2
550 - Earth sciences
2
615 - Pharmacology & therapeutics
2
900 - History & geography
2
304 - Factors affecting social behavior
1
330 - Economics
1
343 - Military, tax, trade & industrial law
1
595 - Arthropods
1
600 - Technology
1
628 - Sanitary & municipal engineering
1
641 - Food & drink
1
690 - Buildings
1
720 - Architecture
1