M- general books, C- meeting minutes, G- compilations, N- newspapers, J- journals, D- papers, R- reports, S- standards, P- patents, D b- databases, [DB/OL]- online databases, [
The document identification code of a periodical is a classification code compiled according to the Data Standard for Retrieval and Evaluation of Academic Journals in China (CD-ROM Edition). Its function is to classify articles according to their contents, so as to facilitate literature statistics and periodical evaluation, determine the scope of literature retrieval and improve the applicability of retrieval results.
Couplets, commonly known as couplets and elegantly called couplets, are a special art form of China culture with the beauty of symmetry and order. I arranged t