Classification
500 - Natural sciences & mathematics
700 - The arts; fine & decorative arts
21
551 - Geology, hydrology & meteorology
15
600 - Technology
12
363 - Other social problems & services
10
620 - Engineering & allied operations
10
333 - Economics of land & energy
7
900 - History & geography
7
000 - Computer science, information & general works
6
576 - Genetics & evolution
5
630 - Agriculture & related technologies
5
100 - Philosophy & psychology
4
530 - Physics
4
580 - Plants (Botany)
4
140 - Specific philosophical schools
3
380 - Commerce, communications & transportation
3
581 - Specific topics in natural history
3
800 - Literature & rhetoric
3
200 - Religion
2
330 - Economics
2
340 - Law
2
520 - Astronomy & allied sciences
2
540 - Chemistry & allied sciences
2
610 - Medicine & health
2
120 - Epistemology, causation & humankind
1
170 - Ethics
1
300 - Social sciences
1
320 - Political science
1
370 - Education
1
400 - Language
1
550 - Earth sciences
1
612 - Human physiology
1