Classification
621 - Applied physics
718
620 - Engineering & allied operations
423
536 - Heat
339
530 - Physics
249
333 - Economics of land & energy
120
540 - Chemistry & allied sciences
103
541 - Physical chemistry
89
000 - Computer science, information & general works
84
531 - Classical mechanics; solid mechanics
84
629 - Other branches of engineering
83
660 - Chemical engineering
81
700 - The arts; fine & decorative arts
78
600 - Technology
76
900 - History & geography
35
330 - Economics
29
363 - Other social problems & services
27
500 - Natural sciences & mathematics
26
551 - Geology, hydrology & meteorology
25
576 - Genetics & evolution
25
515 - Analysis
21
539 - Modern physics
21
580 - Plants (Botany)
19
610 - Medicine & health
19
670 - Manufacturing
17
519 - Probabilities & applied mathematics
16
340 - Law
15
380 - Commerce, communications & transportation
15
546 - Inorganic chemistry
13
547 - Organic chemistry
13
140 - Specific philosophical schools
12
690 - Buildings
11
003 - Systems
10
624 - Civil engineering
10
628 - Sanitary & municipal engineering
10
550 - Earth sciences
9
720 - Architecture
9
662 - Explosives, fuels & related products
8
668 - Technology of other organic products
8
696 - Utilities
8
571 - Physiology & related subjects
7
572 - Biochemistry
7
338 - Production
6
697 - Heating, ventilating & air-conditioning
6
006 - Special computer methods
5
414 - Phonology & phonetics
5
510 - Mathematics
5
537 - Electricity & electronics
5
548 - Crystallography
5
549 - Mineralogy
5
661 - Industrial chemicals
5
more ...