Classification
620 - Engineering & allied operations
600 - Technology
2,927
500 - Natural sciences & mathematics
2,501
900 - History & geography
1,840
005 - Computer programming, programs & data
1,819
700 - The arts; fine & decorative arts
1,259
333 - Economics of land & energy
1,093
621 - Applied physics
1,085
658 - General management
1,078
000 - Computer science, information & general works
1,002
384 - Communications; telecommunication
931
330 - Economics
867
331 - Labor economics
835
363 - Other social problems & services
792
745 - Decorative arts
739
380 - Commerce, communications & transportation
502
610 - Medicine & health
484
630 - Agriculture & related technologies
444
004 - Data processing & computer science
355
580 - Plants (Botany)
338
006 - Special computer methods
332
540 - Chemistry & allied sciences
270
140 - Specific philosophical schools
255
530 - Physics
244
629 - Other branches of engineering
211
576 - Genetics & evolution
200
302 - Social interaction
194
300 - Social sciences
188
551 - Geology, hydrology & meteorology
166
338 - Production
164
320 - Political science
159
720 - Architecture
159
510 - Mathematics
158
374 - Adult education
149
770 - Photography, photographs & computer art
139
370 - Education
119
340 - Law
111
414 - Phonology & phonetics
104
670 - Manufacturing
95
581 - Specific topics in natural history
88
800 - Literature & rhetoric
76
667 - Cleaning, color & coating technologies
75
781 - General principles & musical forms
69
400 - Language
67
660 - Chemical engineering
67
100 - Philosophy & psychology
64
381 - Commerce
63
304 - Factors affecting social behavior
51
681 - Precision instruments & other devices
51
153 - Mental processes & intelligence
45
more ...