Professional retrieval database. The VIP database contains more than 8 million articles published in more than 8,000 periodicals such as natural science, engineering technology, agriculture, medicine and health, economy, education and library and information science since 1989, and its retrieval method does not include professional retrieval database. VIP Chinese periodical database covers seven topics: natural science, engineering technology, agricultural science, medicine and health, economic management, educational science and library and information.