Classification
320 - Political science
153
330 - Economics
142
617 - Surgery & related medical specialties
86
610 - Medicine & health
68
700 - The arts; fine & decorative arts
52
900 - History & geography
51
000 - Computer science, information & general works
39
616 - Diseases
34
140 - Specific philosophical schools
28
333 - Economics of land & energy
23
580 - Plants (Botany)
23
363 - Other social problems & services
21
304 - Factors affecting social behavior
18
600 - Technology
17
570 - Life sciences; biology
16
540 - Chemistry & allied sciences
14
576 - Genetics & evolution
14
620 - Engineering & allied operations
12
380 - Commerce, communications & transportation
11
300 - Social sciences
10
340 - Law
9
615 - Pharmacology & therapeutics
9
414 - Phonology & phonetics
8
820 - English & Old English literatures
7
581 - Specific topics in natural history
6
630 - Agriculture & related technologies
6
551 - Geology, hydrology & meteorology
5
612 - Human physiology
5
618 - Gynecology, obstetrics, pediatrics & geriatrics
4
305 - Social groups
3
500 - Natural sciences & mathematics
3
061 - Organizations in North America
2
100 - Philosophy & psychology
2
170 - Ethics
2
200 - Religion
2
301 - Sociology & anthropology
2
613 - Personal health & safety
2
720 - Architecture
2
972 - Middle America; Mexico
2
296 - Judaism
1
303 - Social processes
1
325 - International migration & colonization
1
346 - Private law
1
370 - Education
1
509 - Historical, geographic & persons treatment
1
572 - Biochemistry
1
591 - Specific topics in natural history
1
636 - Animal husbandry
1
664 - Food technology
1
800 - Literature & rhetoric
1
more ...