Classification
530 - Physics
7,135
620 - Engineering & allied operations
1,928
541 - Physical chemistry
1,769
621 - Applied physics
1,626
539 - Modern physics
1,398
500 - Natural sciences & mathematics
1,141
333 - Economics of land & energy
926
519 - Probabilities & applied mathematics
802
515 - Analysis
744
610 - Medicine & health
685
551 - Geology, hydrology & meteorology
674
520 - Astronomy & allied sciences
586
006 - Special computer methods
551
700 - The arts; fine & decorative arts
545
550 - Earth sciences
541
910 - Geography & travel
525
523 - Specific celestial bodies & phenomena
506
000 - Computer science, information & general works
424
600 - Technology
344
363 - Other social problems & services
324
531 - Classical mechanics; solid mechanics
317
629 - Other branches of engineering
293
543 - Analytical chemistry
258
571 - Physiology & related subjects
255
510 - Mathematics
251
540 - Chemistry & allied sciences
229
900 - History & geography
228
536 - Heat
227
537 - Electricity & electronics
221
547 - Organic chemistry
213
003 - Systems
209
330 - Economics
206
546 - Inorganic chemistry
189
577 - Ecology
188
512 - Algebra
179
370 - Education
178
518 - Numerical analysis
173
616 - Diseases
173
660 - Chemical engineering
173
516 - Geometry
171
380 - Commerce, communications & transportation
170
501 - Philosophy & theory
169
615 - Pharmacology & therapeutics
166
535 - Light & infrared & ultraviolet phenomena
145
140 - Specific philosophical schools
135
572 - Biochemistry
131
004 - Data processing & computer science
128
304 - Factors affecting social behavior
128
570 - Life sciences; biology
118
690 - Buildings
118
more ...