Classification
551 - Geology, hydrology & meteorology
57
620 - Engineering & allied operations
53
630 - Agriculture & related technologies
46
571 - Physiology & related subjects
44
580 - Plants (Botany)
38
616 - Diseases
36
333 - Economics of land & energy
29
577 - Ecology
29
579 - Microorganisms, fungi & algae
28
572 - Biochemistry
23
660 - Chemical engineering
22
541 - Physical chemistry
21
631 - Techniques, equipment & materials
20
664 - Food technology
20
550 - Earth sciences
19
621 - Applied physics
19
006 - Special computer methods
18
547 - Organic chemistry
18
581 - Specific topics in natural history
17
363 - Other social problems & services
16
005 - Computer programming, programs & data
13
530 - Physics
12
641 - Food & drink
12
910 - Geography & travel
12
304 - Factors affecting social behavior
10
612 - Human physiology
10
615 - Pharmacology & therapeutics
10
624 - Civil engineering
10
570 - Life sciences; biology
9
004 - Data processing & computer science
8
546 - Inorganic chemistry
6
610 - Medicine & health
6
613 - Personal health & safety
6
690 - Buildings
6
930 - History of ancient world to ca. 499
6
628 - Sanitary & municipal engineering
4
691 - Building materials
4
338 - Production
3
500 - Natural sciences & mathematics
3
539 - Modern physics
3
540 - Chemistry & allied sciences
3
003 - Systems
2
327 - International relations
2
518 - Numerical analysis
2
519 - Probabilities & applied mathematics
2
520 - Astronomy & allied sciences
2
549 - Mineralogy
2
576 - Genetics & evolution
2
578 - Natural history of organisms
2
614 - Incidence & prevention of disease
2
more ...