VIP has the longest collection time and Wanfang has the shortest collection time, but Wanfang is the best in this issue, and many VIP journals are gone, especially medical journals.

Second, search results.

China HowNet has the most results, followed by VIP and Wanfang.

Third, the classification methods are different.

China HowNet can classify and analyze the obtained documents by year, source database, source of publication, author, research level, fund support, Chinese keywords, author unit, etc. VIP can classify and analyze the obtained documents according to all journals, core journals, CSSCI journals, journal documents in the last five years, journal documents in the last three years and journal documents in the last year, and can classify the obtained documents according to paper type, year, journal and academic category.

Four. News report

Wanfang: natural science, mathematical physics, astronomy, earth, biology, medicine, health, industrial technology, aviation, environment, social science, human geography and other disciplines.

Vip: natural science photo album, agricultural science photo album, medical and health photo album, educational science photo album, economic management photo album, library and information photo album, and engineering technology photo album.

HowNet: Knowledge of natural science, humanities and social sciences and engineering technology, including doctoral and excellent master's degree theses from periodicals, newspapers and doctoral and master's training institutions, and papers from important national conferences.