Classification
330 - Economics
285
630 - Agriculture & related technologies
180
333 - Economics of land & energy
88
610 - Medicine & health
88
320 - Political science
74
363 - Other social problems & services
73
580 - Plants (Botany)
55
000 - Computer science, information & general works
53
600 - Technology
53
551 - Geology, hydrology & meteorology
41
620 - Engineering & allied operations
41
700 - The arts; fine & decorative arts
38
577 - Ecology
31
636 - Animal husbandry
28
571 - Physiology & related subjects
26
616 - Diseases
25
576 - Genetics & evolution
24
140 - Specific philosophical schools
23
304 - Factors affecting social behavior
23
338 - Production
22
361 - Social problems & social welfare in general
20
579 - Microorganisms, fungi & algae
20
570 - Life sciences; biology
19
900 - History & geography
18
581 - Specific topics in natural history
17
006 - Special computer methods
16
380 - Commerce, communications & transportation
16
664 - Food technology
16
300 - Social sciences
15
590 - Animals (Zoology)
15
631 - Techniques, equipment & materials
12
641 - Food & drink
12
658 - General management
12
628 - Sanitary & municipal engineering
11
660 - Chemical engineering
11
301 - Sociology & anthropology
8
615 - Pharmacology & therapeutics
8
621 - Applied physics
8
910 - Geography & travel
8
004 - Data processing & computer science
7
370 - Education
7
550 - Earth sciences
7
591 - Specific topics in natural history
7
001 - Knowledge
6
613 - Personal health & safety
6
634 - Orchards, fruits & forestry
6
500 - Natural sciences & mathematics
5
540 - Chemistry & allied sciences
5
005 - Computer programming, programs & data
4
170 - Ethics
4
more ...