Classification
330 - Economics
56
320 - Political science
38
006 - Special computer methods
31
590 - Animals (Zoology)
26
333 - Economics of land & energy
22
577 - Ecology
21
900 - History & geography
20
576 - Genetics & evolution
17
700 - The arts; fine & decorative arts
17
620 - Engineering & allied operations
16
000 - Computer science, information & general works
15
600 - Technology
14
005 - Computer programming, programs & data
12
340 - Law
12
658 - General management
12
363 - Other social problems & services
11
621 - Applied physics
10
004 - Data processing & computer science
9
301 - Sociology & anthropology
9
630 - Agriculture & related technologies
9
610 - Medicine & health
8
612 - Human physiology
8
790 - Recreational & performing arts
8
140 - Specific philosophical schools
7
551 - Geology, hydrology & meteorology
7
300 - Social sciences
6
331 - Labor economics
6
332 - Financial economics
6
380 - Commerce, communications & transportation
6
500 - Natural sciences & mathematics
6
910 - Geography & travel
6
302 - Social interaction
5
519 - Probabilities & applied mathematics
5
305 - Social groups
4
384 - Communications; telecommunication
4
550 - Earth sciences
4
571 - Physiology & related subjects
4
572 - Biochemistry
4
641 - Food & drink
4
664 - Food technology
4
820 - English & Old English literatures
4
304 - Factors affecting social behavior
3
374 - Adult education
3
381 - Commerce
3
400 - Language
3
580 - Plants (Botany)
3
591 - Specific topics in natural history
3
616 - Diseases
3
720 - Architecture
3
741 - Drawing & drawings
3
more ...