The following are the general subject areas in the Library of Congress Subject Headings for Sciences.
Q 1-390 - Science (General)
QA 1-939 - Mathematics
(Also within Mathematics are:
QA 75.5-76.95 Electronic computers. Computer science
QA 76.75-76.765 Computer software)
QB 1-991- Astronomy
QC 1-999 - Physics
QD 1-999 - Chemistry
QE 1-996.5 - Geology
QH 1-278.5.- Natural history -
QH 301-705.5- Biology
QK 1-989 - Botany
QL 1- 991 - Zoology
QM 1-695 - Human anatomy
QP1-981 - Physiology
QR 1-502 - Microbiologyy
Further breakdowns within these classifications may be viewed in the Library of Congress Classification Outline for Class Q.