Classification
520 - Astronomy & allied sciences
128
500 - Natural sciences & mathematics
69
629 - Other branches of engineering
49
523 - Specific celestial bodies & phenomena
23
551 - Geology, hydrology & meteorology
15
600 - Technology
13
550 - Earth sciences
5
526 - Mathematical geography
4
530 - Physics
4
576 - Genetics & evolution
4
539 - Modern physics
3
363 - Other social problems & services
2
620 - Engineering & allied operations
2
338 - Production
1
341 - Law of nations
1
515 - Analysis
1
536 - Heat
1
541 - Physical chemistry
1
570 - Life sciences; biology
1
571 - Physiology & related subjects
1
577 - Ecology
1
615 - Pharmacology & therapeutics
1
621 - Applied physics
1
628 - Sanitary & municipal engineering
1
900 - History & geography
1