Classification
620 - Engineering & allied operations
318
005 - Computer programming, programs & data
307
621 - Applied physics
284
006 - Special computer methods
270
004 - Data processing & computer science
265
530 - Physics
190
330 - Economics
157
515 - Analysis
129
003 - Systems
127
658 - General management
114
629 - Other branches of engineering
110
519 - Probabilities & applied mathematics
93
616 - Diseases
79
577 - Ecology
73
500 - Natural sciences & mathematics
65
551 - Geology, hydrology & meteorology
63
571 - Physiology & related subjects
54
331 - Labor economics
49
531 - Classical mechanics; solid mechanics
49
333 - Economics of land & energy
48
541 - Physical chemistry
45
610 - Medicine & health
44
338 - Production
42
670 - Manufacturing
41
520 - Astronomy & allied sciences
40
300 - Social sciences
36
539 - Modern physics
36
570 - Life sciences; biology
32
624 - Civil engineering
31
630 - Agriculture & related technologies
30
510 - Mathematics
29
612 - Human physiology
29
304 - Factors affecting social behavior
26
550 - Earth sciences
26
660 - Chemical engineering
25
001 - Knowledge
23
332 - Financial economics
23
518 - Numerical analysis
23
523 - Specific celestial bodies & phenomena
23
572 - Biochemistry
23
384 - Communications; telecommunication
21
000 - Computer science, information & general works
20
580 - Plants (Botany)
20
745 - Decorative arts
20
617 - Surgery & related medical specialties
17
511 - General principles of mathematics
16
512 - Algebra
16
910 - Geography & travel
16
363 - Other social problems & services
14
536 - Heat
14
more ...