Classification
600 - Technology
2,168
330 - Economics
677
621 - Applied physics
546
620 - Engineering & allied operations
511
363 - Other social problems & services
444
320 - Political science
293
333 - Economics of land & energy
230
610 - Medicine & health
168
304 - Factors affecting social behavior
161
303 - Social processes
149
900 - History & geography
126
370 - Education
122
629 - Other branches of engineering
91
380 - Commerce, communications & transportation
85
700 - The arts; fine & decorative arts
85
630 - Agriculture & related technologies
73
658 - General management
68
005 - Computer programming, programs & data
57
551 - Geology, hydrology & meteorology
57
540 - Chemistry & allied sciences
49
530 - Physics
47
306 - Culture & institutions
45
006 - Special computer methods
43
581 - Specific topics in natural history
41
300 - Social sciences
37
519 - Probabilities & applied mathematics
34
670 - Manufacturing
34
500 - Natural sciences & mathematics
30
580 - Plants (Botany)
30
004 - Data processing & computer science
27
003 - Systems
26
140 - Specific philosophical schools
26
000 - Computer science, information & general works
24
336 - Public finance
20
624 - Civil engineering
18
302 - Social interaction
16
660 - Chemical engineering
16
301 - Sociology & anthropology
15
664 - Food technology
13
690 - Buildings
13
641 - Food & drink
12
338 - Production
11
576 - Genetics & evolution
11
628 - Sanitary & municipal engineering
11
800 - Literature & rhetoric
11
100 - Philosophy & psychology
10
305 - Social groups
10
340 - Law
10
539 - Modern physics
10
361 - Social problems & social welfare in general
8
more ...