Classification
620 - Engineering & allied operations
1,476
333 - Economics of land & energy
1,237
330 - Economics
1,112
363 - Other social problems & services
786
600 - Technology
717
700 - The arts; fine & decorative arts
587
551 - Geology, hydrology & meteorology
538
621 - Applied physics
432
000 - Computer science, information & general works
430
900 - History & geography
383
577 - Ecology
333
580 - Plants (Botany)
305
540 - Chemistry & allied sciences
291
610 - Medicine & health
287
541 - Physical chemistry
284
530 - Physics
253
630 - Agriculture & related technologies
239
380 - Commerce, communications & transportation
230
660 - Chemical engineering
208
547 - Organic chemistry
198
304 - Factors affecting social behavior
184
500 - Natural sciences & mathematics
165
320 - Political science
162
006 - Special computer methods
148
571 - Physiology & related subjects
135
576 - Genetics & evolution
135
658 - General management
122
616 - Diseases
119
572 - Biochemistry
118
550 - Earth sciences
105
140 - Specific philosophical schools
103
579 - Microorganisms, fungi & algae
98
581 - Specific topics in natural history
94
338 - Production
93
628 - Sanitary & municipal engineering
88
414 - Phonology & phonetics
81
300 - Social sciences
80
720 - Architecture
72
546 - Inorganic chemistry
70
520 - Astronomy & allied sciences
67
615 - Pharmacology & therapeutics
67
629 - Other branches of engineering
66
612 - Human physiology
64
910 - Geography & travel
64
631 - Techniques, equipment & materials
63
001 - Knowledge
60
543 - Analytical chemistry
54
549 - Mineralogy
51
634 - Orchards, fruits & forestry
50
624 - Civil engineering
48
more ...