(1) Unprocessed and published manuscripts, original data records and other documents belong to zero-level documents and are the basis of first-level documents.
(2) Monographs, newspapers, periodicals, patent documents, standard documents, conference documents, samples and other finished documents belong to the original documents;
(3) Re-processing, sorting, refining and compressing the first-class documents, and sorting them according to their external characteristics (title, author, physical characteristics of documents) and content characteristics to form another new document form-catalogue, bibliography, index and abstract, which is the second-class documents;
(4) Using the secondary literature, select the relevant primary literature, and then analyze and synthesize it to compile the tertiary literature forms-special reports, reviews, progress, manuals, encyclopedias, yearbooks and other reference books, which are the tertiary literature.
Extended data:
The traditional enumeration classification is gradually developing to faceted combination classification. Including: continue to improve the classification of facet combination, so as to achieve the purpose of practical application; Transform the traditional enumeration classification to make it gradually develop into noodle formula; Enumeration taxonomy is used in combination with faceted combination taxonomy.
Classification and subject method gradually tend to merge. Classification and subject method are increasingly compatible in concept (terminology) system, reference system, indexing system, indexing system and retrieval system. Literature classification tends to standardization and internationalization. ⑤ The compilation, management, indexing and retrieval of document classification tables are becoming more and more automatic.
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