Classification
551 - Geology, hydrology & meteorology
1,519
624 - Civil engineering
594
550 - Earth sciences
420
333 - Economics of land & energy
277
363 - Other social problems & services
229
910 - Geography & travel
215
577 - Ecology
212
620 - Engineering & allied operations
189
549 - Mineralogy
146
621 - Applied physics
130
700 - The arts; fine & decorative arts
109
330 - Economics
95
900 - History & geography
90
560 - Paleontology; paleozoology
79
300 - Social sciences
72
576 - Genetics & evolution
68
600 - Technology
64
414 - Phonology & phonetics
61
500 - Natural sciences & mathematics
60
000 - Computer science, information & general works
57
001 - Knowledge
57
526 - Mathematical geography
57
006 - Special computer methods
55
320 - Political science
53
540 - Chemistry & allied sciences
53
553 - Economic geology
53
530 - Physics
52
631 - Techniques, equipment & materials
51
519 - Probabilities & applied mathematics
47
628 - Sanitary & municipal engineering
46
520 - Astronomy & allied sciences
42
523 - Specific celestial bodies & phenomena
42
541 - Physical chemistry
42
304 - Factors affecting social behavior
40
690 - Buildings
40
630 - Agriculture & related technologies
36
570 - Life sciences; biology
34
003 - Systems
31
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
24
380 - Commerce, communications & transportation
21
571 - Physiology & related subjects
21
610 - Medicine & health
21
579 - Microorganisms, fungi & algae
20
691 - Building materials
18
140 - Specific philosophical schools
17
340 - Law
17
more ...