Classification
520 - Astronomy & allied sciences
1,023
523 - Specific celestial bodies & phenomena
703
530 - Physics
364
500 - Natural sciences & mathematics
209
539 - Modern physics
187
333 - Economics of land & energy
32
550 - Earth sciences
29
621 - Applied physics
28
300 - Social sciences
26
519 - Probabilities & applied mathematics
25
576 - Genetics & evolution
24
620 - Engineering & allied operations
23
001 - Knowledge
22
700 - The arts; fine & decorative arts
21
551 - Geology, hydrology & meteorology
20
004 - Data processing & computer science
18
515 - Analysis
17
518 - Numerical analysis
17
006 - Special computer methods
16
541 - Physical chemistry
16
000 - Computer science, information & general works
14
531 - Classical mechanics; solid mechanics
14
532 - Fluid mechanics; liquid mechanics
13
629 - Other branches of engineering
13
537 - Electricity & electronics
12
005 - Computer programming, programs & data
11
510 - Mathematics
11
570 - Life sciences; biology
10
003 - Systems
9
370 - Education
9
306 - Culture & institutions
8
501 - Philosophy & theory
7
536 - Heat
7
535 - Light & infrared & ultraviolet phenomena
6
526 - Mathematical geography
5
540 - Chemistry & allied sciences
5
572 - Biochemistry
5
509 - Historical, geographic & persons treatment
4
533 - Gas mechanics
4
534 - Sound & related vibrations
4
538 - Magnetism
4
658 - General management
4
910 - Geography & travel
4
330 - Economics
3
331 - Labor economics
3
516 - Geometry
3
546 - Inorganic chemistry
3
571 - Physiology & related subjects
3
628 - Sanitary & municipal engineering
3
040 - [Unassigned]
2
more ...