Book classification
The first level is divided into humanities books and nature books according to the attributes of the universe.
The second level is divided according to the basic subject attributes of books.
Basic humanities subjects: philosophy A, religion B, ethics C, logic D, aesthetics E, psychology F, language G, literature H, art I, politics J, economy K, military L, law M, education N, sports O, media P, information Q, management R, business S, history T, archaeology U, nationality V, life W, wealth X.
Natural basic disciplines: A astronomy, B geography, C mathematics, D physics, E chemistry, F biology, G machinery, H telecommunications, I water conservancy, J electric power, K textile, L food, M architecture, N mine, O metallurgy, P energy, Q transportation, R aerospace, S medicine, T engineering, U agriculture, V forestry, W aquaculture, X computer.
The third level is divided according to the standards of books affiliated disciplines.
The fourth level is divided by the functional attributes of books (writing, learning, teaching and helping).
The fifth level divides books into works (works, theoretical works and applied works) and academics (comments, comments, argumentation, discussion, research, textual research and translation) according to their category attributes.
Teaching (school textbooks, social training textbooks, self-study textbooks, reference materials, handouts, learning materials, popular reading materials, experimental exercises, test questions and exercises, syllabus), help (dictionaries, encyclopedias, books, government books, yearbooks, manuals, bibliographies, indexes, abstracts, tables, catalogues, standards).
The sixth level is divided into domestic and foreign original books (non-disciplinary definition space) according to the international space of books.
The seventh level is divided into book time series (non-disciplinary time series).