Classification
621 - Applied physics
26
551 - Geology, hydrology & meteorology
21
333 - Economics of land & energy
18
576 - Genetics & evolution
15
363 - Other social problems & services
11
560 - Paleontology; paleozoology
11
620 - Engineering & allied operations
11
577 - Ecology
10
330 - Economics
9
550 - Earth sciences
9
300 - Social sciences
6
590 - Animals (Zoology)
6
001 - Knowledge
5
660 - Chemical engineering
5
541 - Physical chemistry
4
580 - Plants (Botany)
4
910 - Geography & travel
4
301 - Sociology & anthropology
3
304 - Factors affecting social behavior
3
536 - Heat
3
571 - Physiology & related subjects
3
628 - Sanitary & municipal engineering
3
005 - Computer programming, programs & data
2
006 - Special computer methods
2
036 - Encyclopedias in Spanish & Portuguese
2
306 - Culture & institutions
2
320 - Political science
2
332 - Financial economics
2
338 - Production
2
388 - Transportation; ground transportation
2
570 - Life sciences; biology
2
572 - Biochemistry
2
579 - Microorganisms, fungi & algae
2
631 - Techniques, equipment & materials
2
662 - Explosives, fuels & related products
2
000 - Computer science, information & general works
1
003 - Systems
1
153 - Mental processes & intelligence
1
340 - Law
1
495 - Languages of East & Southeast Asia
1
519 - Probabilities & applied mathematics
1
520 - Astronomy & allied sciences
1
526 - Mathematical geography
1
531 - Classical mechanics; solid mechanics
1
540 - Chemistry & allied sciences
1
553 - Economic geology
1
596 - Chordates
1
599 - Mammals
1
612 - Human physiology
1
616 - Diseases
1
more ...