Classification
620 - Engineering & allied operations
530
670 - Manufacturing
68
621 - Applied physics
52
629 - Other branches of engineering
23
530 - Physics
14
531 - Classical mechanics; solid mechanics
14
660 - Chemical engineering
12
628 - Sanitary & municipal engineering
10
691 - Building materials
9
624 - Civil engineering
8
667 - Cleaning, color & coating technologies
7
541 - Physical chemistry
6
363 - Other social problems & services
4
610 - Medicine & health
4
690 - Buildings
4
500 - Natural sciences & mathematics
3
537 - Electricity & electronics
3
600 - Technology
3
720 - Architecture
3
900 - History & geography
3
003 - Systems
2
140 - Specific philosophical schools
2
333 - Economics of land & energy
2
338 - Production
2
539 - Modern physics
2
546 - Inorganic chemistry
2
550 - Earth sciences
2
577 - Ecology
2
617 - Surgery & related medical specialties
2
700 - The arts; fine & decorative arts
2
005 - Computer programming, programs & data
1
303 - Social processes
1
304 - Factors affecting social behavior
1
321 - Systems of governments & states
1
515 - Analysis
1
519 - Probabilities & applied mathematics
1
520 - Astronomy & allied sciences
1
536 - Heat
1
540 - Chemistry & allied sciences
1
543 - Analytical chemistry
1
547 - Organic chemistry
1
580 - Plants (Botany)
1
607 - Education, research & related topics
1
658 - General management
1
693 - Specific materials & purposes
1
696 - Utilities
1