Classification
333 - Economics of land & energy
740
621 - Applied physics
476
338 - Production
248
304 - Factors affecting social behavior
92
658 - General management
60
363 - Other social problems & services
52
620 - Engineering & allied operations
49
629 - Other branches of engineering
43
321 - Systems of governments & states
30
660 - Chemical engineering
29
551 - Geology, hydrology & meteorology
26
720 - Architecture
25
320 - Political science
23
628 - Sanitary & municipal engineering
21
696 - Utilities
21
006 - Special computer methods
20
330 - Economics
16
670 - Manufacturing
16
003 - Systems
15
630 - Agriculture & related technologies
15
577 - Ecology
14
530 - Physics
13
624 - Civil engineering
12
910 - Geography & travel
12
690 - Buildings
11
340 - Law
10
004 - Data processing & computer science
9
343 - Military, tax, trade & industrial law
9
650 - Management & auxiliary services
9
332 - Financial economics
8
344 - Labor, social, education & cultural law
7
631 - Techniques, equipment & materials
7
327 - International relations
6
303 - Social processes
5
337 - International economics
5
519 - Probabilities & applied mathematics
5
536 - Heat
5
541 - Physical chemistry
5
627 - Hydraulic engineering
5
300 - Social sciences
4
339 - Macroeconomics & related topics
4
341 - Law of nations
4
301 - Sociology & anthropology
3
352 - General considerations of public administration
3
547 - Organic chemistry
3
550 - Earth sciences
3
579 - Microorganisms, fungi & algae
3
600 - Technology
3
667 - Cleaning, color & coating technologies
3
697 - Heating, ventilating & air-conditioning
3
more ...