Classification
509 - Historical, geographic & persons treatment
157
520 - Astronomy & allied sciences
98
501 - Philosophy & theory
93
510 - Mathematics
83
530 - Physics
64
306 - Culture & institutions
36
620 - Engineering & allied operations
32
621 - Applied physics
29
570 - Life sciences; biology
25
109 - Historical & collected persons treatment
22
540 - Chemistry & allied sciences
22
500 - Natural sciences & mathematics
21
004 - Data processing & computer science
17
344 - Labor, social, education & cultural law
17
576 - Genetics & evolution
17
629 - Other branches of engineering
16
100 - Philosophy & psychology
12
610 - Medicine & health
12
612 - Human physiology
12
300 - Social sciences
11
304 - Factors affecting social behavior
11
809 - History, description & criticism
11
150 - Psychology
10
333 - Economics of land & energy
10
616 - Diseases
10
909 - World history
10
190 - Modern western philosophy
9
303 - Social processes
9
551 - Geology, hydrology & meteorology
9
940 - History of Europe
9
006 - Special computer methods
8
301 - Sociology & anthropology
8
330 - Economics
8
507 - Education, research & related topics
8
600 - Technology
8
001 - Knowledge
7
320 - Political science
7
539 - Modern physics
7
550 - Earth sciences
7
571 - Physiology & related subjects
7
941 - British Isles
7
363 - Other social problems & services
5
370 - Education
5
531 - Classical mechanics; solid mechanics
5
547 - Organic chemistry
5
580 - Plants (Botany)
5
120 - Epistemology, causation & humankind
4
174 - Occupational ethics
4
210 - Philosophy & theory of religion
4
327 - International relations
4
more ...