Classification
539 - Modern physics
41
530 - Physics
11
500 - Natural sciences & mathematics
5
333 - Economics of land & energy
4
520 - Astronomy & allied sciences
3
621 - Applied physics
3
001 - Knowledge
2
300 - Social sciences
2
523 - Specific celestial bodies & phenomena
2
006 - Special computer methods
1
380 - Commerce, communications & transportation
1
576 - Genetics & evolution
1
600 - Technology
1
620 - Engineering & allied operations
1
660 - Chemical engineering
1
900 - History & geography
1