Classification
006 - Special computer methods
121
005 - Computer programming, programs & data
91
004 - Data processing & computer science
86
330 - Economics
58
610 - Medicine & health
58
300 - Social sciences
53
370 - Education
52
371 - Schools & their activities; special education
51
304 - Factors affecting social behavior
47
621 - Applied physics
44
616 - Diseases
41
333 - Economics of land & energy
36
500 - Natural sciences & mathematics
36
658 - General management
36
306 - Culture & institutions
33
519 - Probabilities & applied mathematics
32
620 - Engineering & allied operations
29
150 - Psychology
26
003 - Systems
25
301 - Sociology & anthropology
25
507 - Education, research & related topics
24
320 - Political science
23
510 - Mathematics
21
001 - Knowledge
20
577 - Ecology
18
302 - Social interaction
16
629 - Other branches of engineering
16
613 - Personal health & safety
15
670 - Manufacturing
15
155 - Differential & developmental psychology
14
338 - Production
14
614 - Incidence & prevention of disease
13
615 - Pharmacology & therapeutics
13
040 - [Unassigned]
12
551 - Geology, hydrology & meteorology
12
025 - Library operations
11
571 - Physiology & related subjects
11
617 - Surgery & related medical specialties
11
910 - Geography & travel
11
363 - Other social problems & services
10
650 - Management & auxiliary services
10
303 - Social processes
9
305 - Social groups
9
331 - Labor economics
9
361 - Social problems & social welfare in general
9
501 - Philosophy & theory
9
530 - Physics
9
570 - Life sciences; biology
9
378 - Higher education
8
612 - Human physiology
8
more ...