| CLASSİFİCATİON CODE | SUBJECT HEADINGS |
| A | General works |
| B | Philosophy, Religion |
| B - BJ | Philosophy, Psychology |
| BL - BX | Religion |
| C | Auxiliary sciences of history |
| CB | History of civilization |
| CC | Archaeology |
| CT | Biography |
| D | History (General, Except America) |
| D - DR | History (Europe) |
| DS - DX | History of Asia, Africa, Australia etc. |
| E | History (North America) |
| E | History (South America) |
| G | Geography, Anthropology, Recreation |
| H | Social sciences |
| HA | Statistics |
| HB - HE | Economics |
| HF | Commerce |
| HG - HJ | Finance |
| HM - HX | Sociology |
| J | Political science |
| K | Law |
| L | Education |
| M | Music |
| N | Fine arts |
| P | Language and Literature |
| PA | Greek literature |
| PC | French language |
| PE | English language |
| PF | German language |
| PG | Russian language and literature |
| PL | Languages of Eastern Asia, Africa |
| PL 101-271 | Turkish language and literature |
| PQ | French literature |
| PR | English literature |
| PS | American literature |
| PT | German literature |
| Q | Science |
| QA | Mathematics, Statistics, Computer science |
| QB | Astronomy |
| QC | Physics |
| QD | Chemistry |
| QE | Geology |
| QH | Biology |
| QK | Botany |
| QL | Zoology |
| QM | Human anatomy |
| QP | Biochemistry |
| QR | Microbiology |
| QT | Physiology |
| QU | Biochemistry, Nutrition |
| QV | Pharmacology |
| QW | Microbiology and Immunology |
| QZ | Pathology |
| R | Medicine |
| S | Agriculture |
| SB | Plant culture |
| SD | Forestry |
| SF | Animal culture |
| T | Technology and Enginnering |
| TA | Engineering, Civil engineering |
| TC | Hydraulic engineering |
| TD | Environmental technology |
| TE | Highway engineering |
| TF | Railroad engineering |
| TG | Bridge engineering |
| TH | Building, Construction |
| TJ | Mechanical engineering |
| TK | Electrical engineering |
| TL | Motor vehicles, Aeroneutics |
| TN | Mining engineering, Metallurgy |
| TP | Chemical technology |
| TR | Photography |
| TS | Manufactures |
| TT | Handicrafts |
| TX | Home economics |
| U | Military science |
| V | Naval science |
| Z | Bibliography and Library science |
