Classification
541 - Physical chemistry
82
551 - Geology, hydrology & meteorology
65
520 - Astronomy & allied sciences
53
523 - Specific celestial bodies & phenomena
50
530 - Physics
39
515 - Analysis
29
547 - Organic chemistry
26
519 - Probabilities & applied mathematics
18
512 - Algebra
16
539 - Modern physics
14
550 - Earth sciences
13
621 - Applied physics
13
511 - General principles of mathematics
12
543 - Analytical chemistry
11
546 - Inorganic chemistry
10
572 - Biochemistry
9
510 - Mathematics
8
549 - Mineralogy
8
620 - Engineering & allied operations
8
518 - Numerical analysis
7
540 - Chemistry & allied sciences
7
516 - Geometry
6
333 - Economics of land & energy
5
004 - Data processing & computer science
4
500 - Natural sciences & mathematics
3
537 - Electricity & electronics
3
548 - Crystallography
3
003 - Systems
2
005 - Computer programming, programs & data
2
363 - Other social problems & services
2
514 - Topology
2
531 - Classical mechanics; solid mechanics
2
536 - Heat
2
542 - Techniques, equipment & materials
2
571 - Physiology & related subjects
2
624 - Civil engineering
2
001 - Knowledge
1
006 - Special computer methods
1
300 - Social sciences
1
332 - Financial economics
1
534 - Sound & related vibrations
1
538 - Magnetism
1
560 - Paleontology; paleozoology
1
576 - Genetics & evolution
1
577 - Ecology
1
590 - Animals (Zoology)
1
616 - Diseases
1
629 - Other branches of engineering
1
631 - Techniques, equipment & materials
1
660 - Chemical engineering
1
more ...