Classification
330 - Economics
610 - Medicine & health
600 - Technology
132
333 - Economics of land & energy
78
304 - Factors affecting social behavior
76
363 - Other social problems & services
76
000 - Computer science, information & general works
72
700 - The arts; fine & decorative arts
67
320 - Political science
63
370 - Education
56
140 - Specific philosophical schools
48
630 - Agriculture & related technologies
36
620 - Engineering & allied operations
34
380 - Commerce, communications & transportation
31
580 - Plants (Botany)
30
300 - Social sciences
29
658 - General management
25
551 - Geology, hydrology & meteorology
23
900 - History & geography
23
100 - Philosophy & psychology
16
581 - Specific topics in natural history
16
361 - Social problems & social welfare in general
14
500 - Natural sciences & mathematics
13
340 - Law
12
170 - Ethics
9
540 - Chemistry & allied sciences
8
720 - Architecture
8
576 - Genetics & evolution
7
200 - Religion
6
800 - Literature & rhetoric
6
301 - Sociology & anthropology
5
305 - Social groups
3
338 - Production
3
362 - Social welfare problems & services
3
400 - Language
3
530 - Physics
3
657 - Accounting
3
780 - Music
3
297 - Islam, Babism & Bahai Faith
2
336 - Public finance
2
372 - Elementary education
2
612 - Human physiology
2
615 - Pharmacology & therapeutics
2
158 - Applied psychology
1
302 - Social interaction
1
350 - Public administration & military science
1
371 - Schools & their activities; special education
1
384 - Communications; telecommunication
1
520 - Astronomy & allied sciences
1
550 - Earth sciences
1
more ...