Classification
551 - Geology, hydrology & meteorology
23
624 - Civil engineering
15
550 - Earth sciences
14
549 - Mineralogy
7
541 - Physical chemistry
6
570 - Life sciences; biology
5
500 - Natural sciences & mathematics
3
333 - Economics of land & energy
2
579 - Microorganisms, fungi & algae
2
910 - Geography & travel
2
150 - Psychology
1
307 - Communities
1
338 - Production
1
363 - Other social problems & services
1
509 - Historical, geographic & persons treatment
1
520 - Astronomy & allied sciences
1
540 - Chemistry & allied sciences
1
571 - Physiology & related subjects
1
577 - Ecology
1
580 - Plants (Botany)
1
581 - Specific topics in natural history
1
600 - Technology
1
620 - Engineering & allied operations
1
621 - Applied physics
1
628 - Sanitary & municipal engineering
1
690 - Buildings
1