Classification
500 - Natural sciences & mathematics
12,111
004 - Data processing & computer science
11,791
300 - Social sciences
11,636
005 - Computer programming, programs & data
10,835
620 - Engineering & allied operations
8,757
320 - Political science
8,521
650 - Management & auxiliary services
7,935
330 - Economics
7,915
006 - Special computer methods
7,648
610 - Medicine & health
6,197
658 - General management
6,085
600 - Technology
5,631
621 - Applied physics
4,843
333 - Economics of land & energy
3,626
530 - Physics
3,216
001 - Knowledge
3,212
000 - Computer science, information & general works
3,092
519 - Probabilities & applied mathematics
2,893
363 - Other social problems & services
2,829
551 - Geology, hydrology & meteorology
2,764
616 - Diseases
2,641
900 - History & geography
2,610
570 - Life sciences; biology
2,419
700 - The arts; fine & decorative arts
2,374
302 - Social interaction
2,196
580 - Plants (Botany)
2,177
670 - Manufacturing
2,010
338 - Production
1,969
370 - Education
1,934
331 - Labor economics
1,922
003 - Systems
1,769
540 - Chemistry & allied sciences
1,710
520 - Astronomy & allied sciences
1,623
510 - Mathematics
1,603
515 - Analysis
1,571
306 - Culture & institutions
1,556
301 - Sociology & anthropology
1,549
304 - Factors affecting social behavior
1,532
629 - Other branches of engineering
1,512
340 - Law
1,499
571 - Physiology & related subjects
1,304
577 - Ecology
1,286
550 - Earth sciences
1,269
630 - Agriculture & related technologies
1,252
100 - Philosophy & psychology
1,198
150 - Psychology
1,133
384 - Communications; telecommunication
1,120
612 - Human physiology
1,102
664 - Food technology
1,089
910 - Geography & travel
1,060
more ...