Classification
330 - Economics
5,228
331 - Labor economics
1,332
005 - Computer programming, programs & data
1,326
620 - Engineering & allied operations
626
000 - Computer science, information & general works
513
320 - Political science
459
600 - Technology
452
658 - General management
450
700 - The arts; fine & decorative arts
409
500 - Natural sciences & mathematics
337
530 - Physics
330
900 - History & geography
316
333 - Economics of land & energy
296
621 - Applied physics
262
363 - Other social problems & services
251
374 - Adult education
240
610 - Medicine & health
238
380 - Commerce, communications & transportation
208
004 - Data processing & computer science
203
515 - Analysis
184
384 - Communications; telecommunication
154
338 - Production
153
539 - Modern physics
152
364 - Criminology
136
371 - Schools & their activities; special education
129
006 - Special computer methods
122
370 - Education
114
340 - Law
111
300 - Social sciences
109
140 - Specific philosophical schools
95
519 - Probabilities & applied mathematics
94
576 - Genetics & evolution
78
551 - Geology, hydrology & meteorology
77
580 - Plants (Botany)
77
629 - Other branches of engineering
69
100 - Philosophy & psychology
59
660 - Chemical engineering
59
670 - Manufacturing
56
302 - Social interaction
50
150 - Psychology
46
520 - Astronomy & allied sciences
46
540 - Chemistry & allied sciences
46
664 - Food technology
44
543 - Analytical chemistry
41
541 - Physical chemistry
40
630 - Agriculture & related technologies
39
510 - Mathematics
36
003 - Systems
34
368 - Insurance
34
381 - Commerce
34
more ...