Classification
621 - Applied physics
737
620 - Engineering & allied operations
436
536 - Heat
342
530 - Physics
253
333 - Economics of land & energy
122
540 - Chemistry & allied sciences
104
541 - Physical chemistry
93
000 - Computer science, information & general works
86
629 - Other branches of engineering
84
531 - Classical mechanics; solid mechanics
82
660 - Chemical engineering
82
700 - The arts; fine & decorative arts
81
600 - Technology
76
900 - History & geography
35
330 - Economics
29
363 - Other social problems & services
27
500 - Natural sciences & mathematics
27
551 - Geology, hydrology & meteorology
26
576 - Genetics & evolution
25
515 - Analysis
21
539 - Modern physics
21
670 - Manufacturing
21
580 - Plants (Botany)
19
610 - Medicine & health
19
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
550 - Earth sciences
10
624 - Civil engineering
10
628 - Sanitary & municipal engineering
10
720 - Architecture
9
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
523 - Specific celestial bodies & phenomena
5
537 - Electricity & electronics
5
548 - Crystallography
5
549 - Mineralogy
5
661 - Industrial chemicals
5
more ...