Classification
520 - Astronomy & allied sciences
135
500 - Natural sciences & mathematics
73
629 - Other branches of engineering
50
523 - Specific celestial bodies & phenomena
24
330 - Economics
17
551 - Geology, hydrology & meteorology
16
600 - Technology
16
900 - History & geography
11
530 - Physics
6
576 - Genetics & evolution
6
550 - Earth sciences
5
363 - Other social problems & services
4
526 - Mathematical geography
4
620 - Engineering & allied operations
4
140 - Specific philosophical schools
3
300 - Social sciences
3
333 - Economics of land & energy
3
340 - Law
3
539 - Modern physics
3
610 - Medicine & health
3
301 - Sociology & anthropology
2
320 - Political science
2
700 - The arts; fine & decorative arts
2
780 - Music
2
800 - Literature & rhetoric
2
000 - Computer science, information & general works
1
338 - Production
1
341 - Law of nations
1
380 - Commerce, communications & transportation
1
515 - Analysis
1
535 - Light & infrared & ultraviolet phenomena
1
536 - Heat
1
537 - Electricity & electronics
1
540 - Chemistry & allied sciences
1
541 - Physical chemistry
1
570 - Life sciences; biology
1
571 - Physiology & related subjects
1
577 - Ecology
1
615 - Pharmacology & therapeutics
1
616 - Diseases
1
621 - Applied physics
1
628 - Sanitary & municipal engineering
1