Classification
333 - Economics of land & energy
790
330 - Economics
601
363 - Other social problems & services
414
338 - Production
192
000 - Computer science, information & general works
109
551 - Geology, hydrology & meteorology
95
320 - Political science
85
658 - General management
79
700 - The arts; fine & decorative arts
73
304 - Factors affecting social behavior
68
577 - Ecology
67
621 - Applied physics
60
630 - Agriculture & related technologies
44
628 - Sanitary & municipal engineering
34
140 - Specific philosophical schools
33
581 - Specific topics in natural history
30
600 - Technology
30
620 - Engineering & allied operations
29
344 - Labor, social, education & cultural law
28
380 - Commerce, communications & transportation
26
580 - Plants (Botany)
26
550 - Earth sciences
21
610 - Medicine & health
21
900 - History & geography
21
910 - Geography & travel
21
300 - Social sciences
20
340 - Law
17
100 - Philosophy & psychology
14
634 - Orchards, fruits & forestry
14
337 - International economics
13
540 - Chemistry & allied sciences
12
800 - Literature & rhetoric
11
332 - Financial economics
10
336 - Public finance
10
339 - Macroeconomics & related topics
10
500 - Natural sciences & mathematics
10
170 - Ethics
9
301 - Sociology & anthropology
9
174 - Occupational ethics
8
306 - Culture & institutions
7
331 - Labor economics
7
343 - Military, tax, trade & industrial law
7
576 - Genetics & evolution
7
307 - Communities
6
370 - Education
6
624 - Civil engineering
6
631 - Techniques, equipment & materials
6
660 - Chemical engineering
6
720 - Architecture
6
361 - Social problems & social welfare in general
5
more ...