Classification
333 - Economics of land & energy
582
577 - Ecology
449
363 - Other social problems & services
427
551 - Geology, hydrology & meteorology
254
700 - The arts; fine & decorative arts
227
330 - Economics
219
630 - Agriculture & related technologies
208
900 - History & geography
169
000 - Computer science, information & general works
160
631 - Techniques, equipment & materials
144
600 - Technology
141
620 - Engineering & allied operations
140
580 - Plants (Botany)
132
320 - Political science
124
581 - Specific topics in natural history
122
610 - Medicine & health
117
616 - Diseases
94
628 - Sanitary & municipal engineering
74
571 - Physiology & related subjects
69
500 - Natural sciences & mathematics
63
617 - Surgery & related medical specialties
63
615 - Pharmacology & therapeutics
61
910 - Geography & travel
59
140 - Specific philosophical schools
56
340 - Law
51
634 - Orchards, fruits & forestry
49
720 - Architecture
49
380 - Commerce, communications & transportation
48
576 - Genetics & evolution
47
590 - Animals (Zoology)
46
658 - General management
43
591 - Specific topics in natural history
38
579 - Microorganisms, fungi & algae
37
338 - Production
34
624 - Civil engineering
34
304 - Factors affecting social behavior
29
621 - Applied physics
29
300 - Social sciences
27
414 - Phonology & phonetics
27
710 - Civic & landscape art
26
540 - Chemistry & allied sciences
25
344 - Labor, social, education & cultural law
24
370 - Education
24
550 - Earth sciences
24
660 - Chemical engineering
24
570 - Life sciences; biology
22
301 - Sociology & anthropology
20
595 - Arthropods
18
800 - Literature & rhetoric
18
170 - Ethics
16
more ...