Classification
634 - Orchards, fruits & forestry
490
577 - Ecology
433
630 - Agriculture & related technologies
316
330 - Economics
205
580 - Plants (Botany)
171
320 - Political science
150
333 - Economics of land & energy
127
581 - Specific topics in natural history
62
363 - Other social problems & services
60
571 - Physiology & related subjects
58
340 - Law
42
551 - Geology, hydrology & meteorology
39
000 - Computer science, information & general works
38
660 - Chemical engineering
35
700 - The arts; fine & decorative arts
32
631 - Techniques, equipment & materials
28
579 - Microorganisms, fungi & algae
26
620 - Engineering & allied operations
25
600 - Technology
24
910 - Geography & travel
24
610 - Medicine & health
19
572 - Biochemistry
18
304 - Factors affecting social behavior
16
900 - History & geography
16
550 - Earth sciences
13
300 - Social sciences
12
344 - Labor, social, education & cultural law
12
380 - Commerce, communications & transportation
12
616 - Diseases
12
570 - Life sciences; biology
9
590 - Animals (Zoology)
9
664 - Food technology
9
140 - Specific philosophical schools
8
338 - Production
8
592 - Invertebrates
8
621 - Applied physics
8
641 - Food & drink
8
576 - Genetics & evolution
7
578 - Natural history of organisms
7
800 - Literature & rhetoric
7
500 - Natural sciences & mathematics
6
612 - Human physiology
6
624 - Civil engineering
6
301 - Sociology & anthropology
5
370 - Education
5
628 - Sanitary & municipal engineering
5
658 - General management
5
540 - Chemistry & allied sciences
4
614 - Incidence & prevention of disease
4
720 - Architecture
4
more ...