Q - Science (General)
QA - Mathematics
QB - Astronomy
QC - Physics
QD - Chemistry
QE - Geology
QH - Natural history - Biology
QK - Botany
QL - Zoology
QM - Human anatomy
QP - Physiology
QR - Microbiology
For more detailed information, visit the Library of Congress Classification Outline.
Q - Science (General)
QA - Mathematics
QB - Astronomy
QC - Physics
QD - Chemistry
QE - Geology
QH - Natural history - Biology
QK - Botany
QL - Zoology
QM - Human anatomy
QP - Physiology
QR - Microbiology