Classification
620 - Engineering & allied operations
31
519 - Probabilities & applied mathematics
30
621 - Applied physics
21
530 - Physics
18
330 - Economics
17
300 - Social sciences
15
515 - Analysis
15
539 - Modern physics
14
658 - General management
14
004 - Data processing & computer science
13
006 - Special computer methods
13
001 - Knowledge
12
005 - Computer programming, programs & data
12
551 - Geology, hydrology & meteorology
11
333 - Economics of land & energy
10
512 - Algebra
10
301 - Sociology & anthropology
9
610 - Medicine & health
9
338 - Production
8
570 - Life sciences; biology
8
003 - Systems
7
500 - Natural sciences & mathematics
7
520 - Astronomy & allied sciences
7
540 - Chemistry & allied sciences
7
616 - Diseases
7
501 - Philosophy & theory
6
510 - Mathematics
6
571 - Physiology & related subjects
6
577 - Ecology
6
531 - Classical mechanics; solid mechanics
5
576 - Genetics & evolution
5
650 - Management & auxiliary services
5
900 - History & geography
5
320 - Political science
4
590 - Animals (Zoology)
4
600 - Technology
4
612 - Human physiology
4
660 - Chemical engineering
4
700 - The arts; fine & decorative arts
4
050 - General serial publications
3
150 - Psychology
3
200 - Religion
3
306 - Culture & institutions
3
363 - Other social problems & services
3
371 - Schools & their activities; special education
3
410 - Linguistics
3
507 - Education, research & related topics
3
516 - Geometry
3
518 - Numerical analysis
3
541 - Physical chemistry
3
more ...