Classification
551 - Geology, hydrology & meteorology
284
577 - Ecology
68
540 - Chemistry & allied sciences
46
549 - Mineralogy
44
550 - Earth sciences
37
363 - Other social problems & services
30
620 - Engineering & allied operations
20
000 - Computer science, information & general works
17
333 - Economics of land & energy
17
631 - Techniques, equipment & materials
15
553 - Economic geology
14
700 - The arts; fine & decorative arts
14
900 - History & geography
14
541 - Physical chemistry
13
578 - Natural history of organisms
13
624 - Civil engineering
13
523 - Specific celestial bodies & phenomena
12
576 - Genetics & evolution
10
910 - Geography & travel
9
140 - Specific philosophical schools
8
414 - Phonology & phonetics
8
500 - Natural sciences & mathematics
8
628 - Sanitary & municipal engineering
7
720 - Architecture
7
543 - Analytical chemistry
6
581 - Specific topics in natural history
6
590 - Animals (Zoology)
6
572 - Biochemistry
5
660 - Chemical engineering
5
930 - History of ancient world to ca. 499
5
003 - Systems
4
304 - Factors affecting social behavior
4
380 - Commerce, communications & transportation
4
519 - Probabilities & applied mathematics
4
546 - Inorganic chemistry
4
579 - Microorganisms, fungi & algae
4
580 - Plants (Botany)
4
600 - Technology
4
621 - Applied physics
4
330 - Economics
3
610 - Medicine & health
3
691 - Building materials
3
320 - Political science
2
526 - Mathematical geography
2
560 - Paleontology; paleozoology
2
570 - Life sciences; biology
2
571 - Physiology & related subjects
2
634 - Orchards, fruits & forestry
2
100 - Philosophy & psychology
1
301 - Sociology & anthropology
1
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