Classification
551 - Geology, hydrology & meteorology
458
363 - Other social problems & services
49
333 - Economics of land & energy
38
577 - Ecology
31
550 - Earth sciences
23
523 - Specific celestial bodies & phenomena
15
621 - Applied physics
13
910 - Geography & travel
12
531 - Classical mechanics; solid mechanics
11
526 - Mathematical geography
9
520 - Astronomy & allied sciences
8
620 - Engineering & allied operations
8
630 - Agriculture & related technologies
6
003 - Systems
5
571 - Physiology & related subjects
5
580 - Plants (Botany)
5
500 - Natural sciences & mathematics
4
530 - Physics
4
539 - Modern physics
4
624 - Civil engineering
4
629 - Other branches of engineering
4
534 - Sound & related vibrations
3
628 - Sanitary & municipal engineering
3
634 - Orchards, fruits & forestry
3
519 - Probabilities & applied mathematics
2
579 - Microorganisms, fungi & algae
2
581 - Specific topics in natural history
2
005 - Computer programming, programs & data
1
006 - Special computer methods
1
300 - Social sciences
1
301 - Sociology & anthropology
1
320 - Political science
1
344 - Labor, social, education & cultural law
1
370 - Education
1
515 - Analysis
1
536 - Heat
1
537 - Electricity & electronics
1
541 - Physical chemistry
1
560 - Paleontology; paleozoology
1
570 - Life sciences; biology
1
613 - Personal health & safety
1
614 - Incidence & prevention of disease
1
690 - Buildings
1