Classification
551 - Geology, hydrology & meteorology
1,507
624 - Civil engineering
590
550 - Earth sciences
422
333 - Economics of land & energy
282
363 - Other social problems & services
229
577 - Ecology
213
910 - Geography & travel
211
620 - Engineering & allied operations
189
549 - Mineralogy
138
621 - Applied physics
116
700 - The arts; fine & decorative arts
110
330 - Economics
95
900 - History & geography
90
560 - Paleontology; paleozoology
76
576 - Genetics & evolution
68
500 - Natural sciences & mathematics
65
526 - Mathematical geography
65
600 - Technology
64
553 - Economic geology
63
414 - Phonology & phonetics
61
300 - Social sciences
59
000 - Computer science, information & general works
57
320 - Political science
53
540 - Chemistry & allied sciences
53
530 - Physics
51
631 - Techniques, equipment & materials
50
519 - Probabilities & applied mathematics
49
628 - Sanitary & municipal engineering
47
001 - Knowledge
44
006 - Special computer methods
43
520 - Astronomy & allied sciences
43
523 - Specific celestial bodies & phenomena
42
541 - Physical chemistry
41
304 - Factors affecting social behavior
39
690 - Buildings
39
630 - Agriculture & related technologies
35
570 - Life sciences; biology
34
580 - Plants (Botany)
28
930 - History of ancient world to ca. 499
28
531 - Classical mechanics; solid mechanics
27
581 - Specific topics in natural history
25
578 - Natural history of organisms
22
380 - Commerce, communications & transportation
21
571 - Physiology & related subjects
21
610 - Medicine & health
21
662 - Explosives, fuels & related products
21
579 - Microorganisms, fungi & algae
19
590 - Animals (Zoology)
18
140 - Specific philosophical schools
17
340 - Law
17
more ...