Classification
500 - Natural sciences & mathematics
38
621 - Applied physics
25
519 - Probabilities & applied mathematics
18
510 - Mathematics
17
629 - Other branches of engineering
15
620 - Engineering & allied operations
14
509 - Historical, geographic & persons treatment
10
551 - Geology, hydrology & meteorology
10
306 - Culture & institutions
9
520 - Astronomy & allied sciences
9
530 - Physics
9
616 - Diseases
9
320 - Political science
8
658 - General management
8
515 - Analysis
7
516 - Geometry
7
641 - Food & drink
7
664 - Food technology
7
330 - Economics
6
531 - Classical mechanics; solid mechanics
6
650 - Management & auxiliary services
6
900 - History & geography
6
301 - Sociology & anthropology
5
539 - Modern physics
5
004 - Data processing & computer science
4
150 - Psychology
3
302 - Social interaction
3
333 - Economics of land & energy
3
340 - Law
3
361 - Social problems & social welfare in general
3
378 - Higher education
3
501 - Philosophy & theory
3
540 - Chemistry & allied sciences
3
610 - Medicine & health
3
630 - Agriculture & related technologies
3
660 - Chemical engineering
3
670 - Manufacturing
3
006 - Special computer methods
2
155 - Differential & developmental psychology
2
332 - Financial economics
2
343 - Military, tax, trade & industrial law
2
370 - Education
2
512 - Algebra
2
523 - Specific celestial bodies & phenomena
2
535 - Light & infrared & ultraviolet phenomena
2
537 - Electricity & electronics
2
547 - Organic chemistry
2
570 - Life sciences; biology
2
572 - Biochemistry
2
940 - History of Europe
2
more ...