Classification
551 - Geology, hydrology & meteorology
1,051
600 - Technology
397
500 - Natural sciences & mathematics
390
363 - Other social problems & services
382
333 - Economics of land & energy
344
520 - Astronomy & allied sciences
309
620 - Engineering & allied operations
298
550 - Earth sciences
272
621 - Applied physics
271
577 - Ecology
267
523 - Specific celestial bodies & phenomena
260
530 - Physics
179
910 - Geography & travel
153
330 - Economics
150
700 - The arts; fine & decorative arts
143
000 - Computer science, information & general works
122
900 - History & geography
109
540 - Chemistry & allied sciences
102
580 - Plants (Botany)
102
610 - Medicine & health
98
629 - Other branches of engineering
91
630 - Agriculture & related technologies
83
541 - Physical chemistry
76
006 - Special computer methods
72
300 - Social sciences
66
539 - Modern physics
65
519 - Probabilities & applied mathematics
63
320 - Political science
60
380 - Commerce, communications & transportation
60
004 - Data processing & computer science
58
571 - Physiology & related subjects
57
658 - General management
56
616 - Diseases
50
576 - Genetics & evolution
47
628 - Sanitary & municipal engineering
47
660 - Chemical engineering
47
001 - Knowledge
44
531 - Classical mechanics; solid mechanics
41
005 - Computer programming, programs & data
40
664 - Food technology
39
572 - Biochemistry
36
624 - Civil engineering
36
003 - Systems
34
515 - Analysis
34
641 - Food & drink
34
570 - Life sciences; biology
33
140 - Specific philosophical schools
32
304 - Factors affecting social behavior
30
526 - Mathematical geography
30
543 - Analytical chemistry
26
more ...