Classification
500 - Natural sciences & mathematics
33
621 - Applied physics
21
519 - Probabilities & applied mathematics
15
620 - Engineering & allied operations
13
510 - Mathematics
10
320 - Political science
8
551 - Geology, hydrology & meteorology
8
616 - Diseases
8
629 - Other branches of engineering
8
515 - Analysis
7
516 - Geometry
7
530 - Physics
7
531 - Classical mechanics; solid mechanics
6
650 - Management & auxiliary services
6
658 - General management
6
900 - History & geography
5
004 - Data processing & computer science
4
301 - Sociology & anthropology
4
539 - Modern physics
4
641 - Food & drink
4
664 - Food technology
4
150 - Psychology
3
330 - Economics
3
340 - Law
3
378 - Higher education
3
509 - Historical, geographic & persons treatment
3
610 - Medicine & health
3
660 - Chemical engineering
3
343 - Military, tax, trade & industrial law
2
370 - Education
2
523 - Specific celestial bodies & phenomena
2
540 - Chemistry & allied sciences
2
570 - Life sciences; biology
2
572 - Biochemistry
2
670 - Manufacturing
2
690 - Buildings
2
000 - Computer science, information & general works
1
001 - Knowledge
1
006 - Special computer methods
1
100 - Philosophy & psychology
1
120 - Epistemology, causation & humankind
1
304 - Factors affecting social behavior
1
306 - Culture & institutions
1
332 - Financial economics
1
333 - Economics of land & energy
1
336 - Public finance
1
338 - Production
1
342 - Constitutional & administrative law
1
361 - Social problems & social welfare in general
1
371 - Schools & their activities; special education
1
more ...