Classification
621 - Applied physics
1,299
006 - Special computer methods
116
333 - Economics of land & energy
98
629 - Other branches of engineering
95
620 - Engineering & allied operations
71
003 - Systems
44
321 - Systems of governments & states
33
541 - Physical chemistry
25
004 - Data processing & computer science
21
660 - Chemical engineering
17
536 - Heat
15
658 - General management
15
363 - Other social problems & services
12
062 - Organizations in British Isles; in England
10
530 - Physics
10
624 - Civil engineering
10
670 - Manufacturing
9
519 - Probabilities & applied mathematics
8
005 - Computer programming, programs & data
7
304 - Factors affecting social behavior
7
628 - Sanitary & municipal engineering
7
515 - Analysis
6
551 - Geology, hydrology & meteorology
5
577 - Ecology
5
720 - Architecture
5
550 - Earth sciences
4
338 - Production
3
531 - Classical mechanics; solid mechanics
3
539 - Modern physics
3
610 - Medicine & health
3
696 - Utilities
3
910 - Geography & travel
3
303 - Social processes
2
523 - Specific celestial bodies & phenomena
2
537 - Electricity & electronics
2
548 - Crystallography
2
571 - Physiology & related subjects
2
572 - Biochemistry
2
301 - Sociology & anthropology
1
305 - Social groups
1
327 - International relations
1
371 - Schools & their activities; special education
1
500 - Natural sciences & mathematics
1
511 - General principles of mathematics
1
518 - Numerical analysis
1
535 - Light & infrared & ultraviolet phenomena
1
540 - Chemistry & allied sciences
1
560 - Paleontology; paleozoology
1
570 - Life sciences; biology
1
579 - Microorganisms, fungi & algae
1
more ...