Classification
305 - Social groups
326
330 - Economics
192
306 - Culture & institutions
151
320 - Political science
123
304 - Factors affecting social behavior
80
300 - Social sciences
73
301 - Sociology & anthropology
66
370 - Education
55
333 - Economics of land & energy
53
361 - Social problems & social welfare in general
53
340 - Law
49
600 - Technology
46
700 - The arts; fine & decorative arts
46
900 - History & geography
43
140 - Specific philosophical schools
30
307 - Communities
30
620 - Engineering & allied operations
30
000 - Computer science, information & general works
27
339 - Macroeconomics & related topics
26
380 - Commerce, communications & transportation
25
610 - Medicine & health
25
614 - Incidence & prevention of disease
25
338 - Production
24
363 - Other social problems & services
24
327 - International relations
21
331 - Labor economics
20
379 - Public policy issues in education
20
613 - Personal health & safety
20
303 - Social processes
18
342 - Constitutional & administrative law
18
100 - Philosophy & psychology
13
341 - Law of nations
13
658 - General management
13
362 - Social welfare problems & services
12
500 - Natural sciences & mathematics
12
302 - Social interaction
10
364 - Criminology
10
400 - Language
10
170 - Ethics
9
371 - Schools & their activities; special education
9
200 - Religion
7
576 - Genetics & evolution
7
323 - Civil & political rights
6
551 - Geology, hydrology & meteorology
6
571 - Physiology & related subjects
6
780 - Music
6
800 - Literature & rhetoric
6
580 - Plants (Botany)
5
630 - Agriculture & related technologies
5
372 - Elementary education
4
more ...