Classification
551 - Geology, hydrology & meteorology
182
549 - Mineralogy
17
577 - Ecology
9
333 - Economics of land & energy
7
910 - Geography & travel
7
363 - Other social problems & services
6
550 - Earth sciences
5
628 - Sanitary & municipal engineering
5
541 - Physical chemistry
3
560 - Paleontology; paleozoology
3
930 - History of ancient world to ca. 499
3
553 - Economic geology
2
570 - Life sciences; biology
2
580 - Plants (Botany)
2
621 - Applied physics
2
624 - Civil engineering
2
519 - Probabilities & applied mathematics
1
520 - Astronomy & allied sciences
1
530 - Physics
1
543 - Analytical chemistry
1
546 - Inorganic chemistry
1
581 - Specific topics in natural history
1
630 - Agriculture & related technologies
1
631 - Techniques, equipment & materials
1
634 - Orchards, fruits & forestry
1