Classification
621 - Applied physics
224
333 - Economics of land & energy
205
620 - Engineering & allied operations
170
600 - Technology
134
700 - The arts; fine & decorative arts
109
900 - History & geography
84
000 - Computer science, information & general works
71
330 - Economics
57
380 - Commerce, communications & transportation
43
363 - Other social problems & services
35
541 - Physical chemistry
29
580 - Plants (Botany)
29
500 - Natural sciences & mathematics
21
530 - Physics
21
540 - Chemistry & allied sciences
17
720 - Architecture
15
576 - Genetics & evolution
14
610 - Medicine & health
14
629 - Other branches of engineering
10
320 - Political science
8
551 - Geology, hydrology & meteorology
8
321 - Systems of governments & states
7
660 - Chemical engineering
7
414 - Phonology & phonetics
6
140 - Specific philosophical schools
5
340 - Law
5
338 - Production
4
630 - Agriculture & related technologies
4
800 - Literature & rhetoric
4
546 - Inorganic chemistry
3
658 - General management
3
670 - Manufacturing
3
697 - Heating, ventilating & air-conditioning
3
003 - Systems
2
370 - Education
2
547 - Organic chemistry
2
549 - Mineralogy
2
624 - Civil engineering
2
657 - Accounting
2
662 - Explosives, fuels & related products
2
100 - Philosophy & psychology
1
120 - Epistemology, causation & humankind
1
304 - Factors affecting social behavior
1
400 - Language
1
532 - Fluid mechanics; liquid mechanics
1
535 - Light & infrared & ultraviolet phenomena
1
536 - Heat
1
539 - Modern physics
1
542 - Techniques, equipment & materials
1
581 - Specific topics in natural history
1
more ...