Classification
541 - Physical chemistry
1,236
620 - Engineering & allied operations
324
530 - Physics
261
547 - Organic chemistry
127
543 - Analytical chemistry
122
621 - Applied physics
115
546 - Inorganic chemistry
102
539 - Modern physics
100
660 - Chemical engineering
81
540 - Chemistry & allied sciences
72
572 - Biochemistry
68
536 - Heat
49
571 - Physiology & related subjects
49
333 - Economics of land & energy
31
363 - Other social problems & services
29
551 - Geology, hydrology & meteorology
26
548 - Crystallography
23
610 - Medicine & health
23
549 - Mineralogy
19
000 - Computer science, information & general works
18
500 - Natural sciences & mathematics
18
615 - Pharmacology & therapeutics
18
616 - Diseases
17
531 - Classical mechanics; solid mechanics
16
537 - Electricity & electronics
16
664 - Food technology
15
700 - The arts; fine & decorative arts
13
641 - Food & drink
12
577 - Ecology
11
520 - Astronomy & allied sciences
9
542 - Techniques, equipment & materials
7
670 - Manufacturing
7
534 - Sound & related vibrations
6
538 - Magnetism
6
613 - Personal health & safety
6
628 - Sanitary & municipal engineering
6
629 - Other branches of engineering
5
900 - History & geography
5
519 - Probabilities & applied mathematics
4
535 - Light & infrared & ultraviolet phenomena
4
570 - Life sciences; biology
4
576 - Genetics & evolution
4
580 - Plants (Botany)
4
600 - Technology
4
624 - Civil engineering
4
304 - Factors affecting social behavior
3
380 - Commerce, communications & transportation
3
501 - Philosophy & theory
3
630 - Agriculture & related technologies
3
631 - Techniques, equipment & materials
3
more ...