- Library of Congress Subject Areas (55393)
- Q Science (15606)
- Q Science (General) (720)
- QB Astronomy (659)
- QC Physics (1859)
- QD Chemistry (1415)
- QE Geology (58)
- QH Natural history (1549)
- QK Botany (92)
- QL Zoology (354)
- QM Human anatomy (87)
- QR Microbiology (648)
- Q Science (15606)