Classification
577 - Ecology
246
333 - Economics of land & energy
221
363 - Other social problems & services
178
551 - Geology, hydrology & meteorology
150
000 - Computer science, information & general works
145
330 - Economics
136
700 - The arts; fine & decorative arts
121
630 - Agriculture & related technologies
92
580 - Plants (Botany)
84
600 - Technology
82
581 - Specific topics in natural history
77
610 - Medicine & health
75
620 - Engineering & allied operations
58
140 - Specific philosophical schools
56
320 - Political science
54
380 - Commerce, communications & transportation
54
900 - History & geography
44
500 - Natural sciences & mathematics
41
576 - Genetics & evolution
39
304 - Factors affecting social behavior
33
910 - Geography & travel
25
658 - General management
22
550 - Earth sciences
21
634 - Orchards, fruits & forestry
21
570 - Life sciences; biology
20
800 - Literature & rhetoric
20
370 - Education
19
300 - Social sciences
16
540 - Chemistry & allied sciences
16
720 - Architecture
16
340 - Law
15
414 - Phonology & phonetics
12
578 - Natural history of organisms
11
170 - Ethics
9
591 - Specific topics in natural history
9
100 - Philosophy & psychology
8
301 - Sociology & anthropology
8
338 - Production
8
579 - Microorganisms, fungi & algae
7
631 - Techniques, equipment & materials
7
612 - Human physiology
6
530 - Physics
5
571 - Physiology & related subjects
5
628 - Sanitary & municipal engineering
5
400 - Language
4
657 - Accounting
4
006 - Special computer methods
3
344 - Labor, social, education & cultural law
3
361 - Social problems & social welfare in general
2
520 - Astronomy & allied sciences
2
more ...