Classification
520 - Astronomy & allied sciences
1,235
523 - Specific celestial bodies & phenomena
273
500 - Natural sciences & mathematics
133
530 - Physics
74
539 - Modern physics
35
629 - Other branches of engineering
26
621 - Applied physics
20
509 - Historical, geographic & persons treatment
16
510 - Mathematics
12
501 - Philosophy & theory
11
550 - Earth sciences
11
551 - Geology, hydrology & meteorology
11
519 - Probabilities & applied mathematics
8
515 - Analysis
5
537 - Electricity & electronics
5
522 - Techniques, equipment & materials
4
531 - Classical mechanics; solid mechanics
4
541 - Physical chemistry
4
576 - Genetics & evolution
4
620 - Engineering & allied operations
4
006 - Special computer methods
3
526 - Mathematical geography
3
571 - Physiology & related subjects
3
900 - History & geography
3
910 - Geography & travel
3
532 - Fluid mechanics; liquid mechanics
2
533 - Gas mechanics
2
535 - Light & infrared & ultraviolet phenomena
2
770 - Photography, photographs & computer art
2
190 - Modern western philosophy
1
514 - Topology
1
516 - Geometry
1
518 - Numerical analysis
1
534 - Sound & related vibrations
1
536 - Heat
1
540 - Chemistry & allied sciences
1
543 - Analytical chemistry
1
549 - Mineralogy
1
570 - Life sciences; biology
1
572 - Biochemistry
1
579 - Microorganisms, fungi & algae
1