Classification
624 - Civil engineering
633
551 - Geology, hydrology & meteorology
97
363 - Other social problems & services
73
620 - Engineering & allied operations
47
690 - Buildings
46
621 - Applied physics
35
628 - Sanitary & municipal engineering
32
550 - Earth sciences
26
333 - Economics of land & energy
25
531 - Classical mechanics; solid mechanics
19
691 - Building materials
14
660 - Chemical engineering
12
627 - Hydraulic engineering
11
577 - Ecology
9
629 - Other branches of engineering
8
910 - Geography & travel
8
662 - Explosives, fuels & related products
7
006 - Special computer methods
5
304 - Factors affecting social behavior
4
500 - Natural sciences & mathematics
4
519 - Probabilities & applied mathematics
4
526 - Mathematical geography
4
693 - Specific materials & purposes
4
530 - Physics
3
536 - Heat
3
622 - Mining & related operations
3
003 - Systems
2
344 - Labor, social, education & cultural law
2
515 - Analysis
2
532 - Fluid mechanics; liquid mechanics
2
533 - Gas mechanics
2
549 - Mineralogy
2
000 - Computer science, information & general works
1
004 - Data processing & computer science
1
307 - Communities
1
338 - Production
1
352 - General considerations of public administration
1
418 - Standard usage & applied linguistics
1
509 - Historical, geographic & persons treatment
1
541 - Physical chemistry
1
543 - Analytical chemistry
1
553 - Economic geology
1
576 - Genetics & evolution
1
600 - Technology
1
610 - Medicine & health
1
613 - Personal health & safety
1
625 - Engineering of railroads & roads
1
631 - Techniques, equipment & materials
1
658 - General management
1
670 - Manufacturing
1