Classification
551 - Geology, hydrology & meteorology
38
624 - Civil engineering
30
550 - Earth sciences
20
910 - Geography & travel
17
577 - Ecology
14
333 - Economics of land & energy
13
363 - Other social problems & services
9
304 - Factors affecting social behavior
4
560 - Paleontology; paleozoology
4
576 - Genetics & evolution
4
006 - Special computer methods
3
630 - Agriculture & related technologies
3
631 - Techniques, equipment & materials
3
005 - Computer programming, programs & data
2
500 - Natural sciences & mathematics
2
518 - Numerical analysis
2
553 - Economic geology
2
570 - Life sciences; biology
2
590 - Animals (Zoology)
2
620 - Engineering & allied operations
2
621 - Applied physics
2
690 - Buildings
2
930 - History of ancient world to ca. 499
2
003 - Systems
1
004 - Data processing & computer science
1
100 - Philosophy & psychology
1
507 - Education, research & related topics
1
515 - Analysis
1
519 - Probabilities & applied mathematics
1
523 - Specific celestial bodies & phenomena
1
526 - Mathematical geography
1
530 - Physics
1
540 - Chemistry & allied sciences
1
543 - Analytical chemistry
1
546 - Inorganic chemistry
1
549 - Mineralogy
1
578 - Natural history of organisms
1
628 - Sanitary & municipal engineering
1
629 - Other branches of engineering
1
634 - Orchards, fruits & forestry
1
660 - Chemical engineering
1
900 - History & geography
1