Classification
620 - Engineering & allied operations
182
621 - Applied physics
158
530 - Physics
73
539 - Modern physics
25
537 - Electricity & electronics
23
006 - Special computer methods
20
541 - Physical chemistry
19
001 - Knowledge
13
300 - Social sciences
13
500 - Natural sciences & mathematics
12
535 - Light & infrared & ultraviolet phenomena
11
660 - Chemical engineering
11
546 - Inorganic chemistry
10
548 - Crystallography
10
670 - Manufacturing
10
004 - Data processing & computer science
9
571 - Physiology & related subjects
9
572 - Biochemistry
9
629 - Other branches of engineering
9
531 - Classical mechanics; solid mechanics
8
520 - Astronomy & allied sciences
7
543 - Analytical chemistry
7
538 - Magnetism
6
547 - Organic chemistry
6
540 - Chemistry & allied sciences
5
005 - Computer programming, programs & data
4
333 - Economics of land & energy
4
519 - Probabilities & applied mathematics
4
610 - Medicine & health
4
617 - Surgery & related medical specialties
4
630 - Agriculture & related technologies
4
681 - Precision instruments & other devices
4
003 - Systems
3
384 - Communications; telecommunication
3
549 - Mineralogy
3
550 - Earth sciences
3
577 - Ecology
3
611 - Human anatomy, cytology & histology
3
616 - Diseases
3
000 - Computer science, information & general works
2
050 - General serial publications
2
302 - Social interaction
2
330 - Economics
2
331 - Labor economics
2
510 - Mathematics
2
515 - Analysis
2
600 - Technology
2
658 - General management
2
745 - Decorative arts
2
153 - Mental processes & intelligence
1
more ...