Classification
520 - Astronomy & allied sciences
326
530 - Physics
59
523 - Specific celestial bodies & phenomena
38
539 - Modern physics
15
500 - Natural sciences & mathematics
10
370 - Education
9
629 - Other branches of engineering
9
550 - Earth sciences
7
551 - Geology, hydrology & meteorology
7
510 - Mathematics
6
621 - Applied physics
6
306 - Culture & institutions
5
526 - Mathematical geography
5
576 - Genetics & evolution
5
301 - Sociology & anthropology
3
509 - Historical, geographic & persons treatment
3
515 - Analysis
3
519 - Probabilities & applied mathematics
3
541 - Physical chemistry
3
333 - Economics of land & energy
2
338 - Production
2
341 - Law of nations
2
379 - Public policy issues in education
2
100 - Philosophy & psychology
1
170 - Ethics
1
305 - Social groups
1
320 - Political science
1
378 - Higher education
1
501 - Philosophy & theory
1
518 - Numerical analysis
1
535 - Light & infrared & ultraviolet phenomena
1
537 - Electricity & electronics
1
572 - Biochemistry
1
620 - Engineering & allied operations
1