Classification
576 - Genetics & evolution
47
520 - Astronomy & allied sciences
46
523 - Specific celestial bodies & phenomena
30
500 - Natural sciences & mathematics
24
551 - Geology, hydrology & meteorology
7
578 - Natural history of organisms
6
570 - Life sciences; biology
5
530 - Physics
4
579 - Microorganisms, fungi & algae
4
629 - Other branches of engineering
4
540 - Chemistry & allied sciences
3
000 - Computer science, information & general works
2
200 - Religion
2
363 - Other social problems & services
2
541 - Physical chemistry
2
547 - Organic chemistry
2
581 - Specific topics in natural history
2
700 - The arts; fine & decorative arts
2
100 - Philosophy & psychology
1
140 - Specific philosophical schools
1
160 - Logic
1
170 - Ethics
1
301 - Sociology & anthropology
1
304 - Factors affecting social behavior
1
320 - Political science
1
330 - Economics
1
333 - Economics of land & energy
1
380 - Commerce, communications & transportation
1
539 - Modern physics
1
549 - Mineralogy
1
550 - Earth sciences
1
572 - Biochemistry
1
580 - Plants (Botany)
1
600 - Technology
1
612 - Human physiology
1
620 - Engineering & allied operations
1
621 - Applied physics
1
628 - Sanitary & municipal engineering
1
900 - History & geography
1