Generally speaking, China Knowledge Network and Wanfang have different strictness in duplicate checking, but which is more stringent needs to be comprehensively judged according to factors such as school requirements, paper types and database of duplicate checking system.

1 Database coverage: China HowNet has an extensive and constantly updated database, including academic journals, doctoral and master's dissertations, conference papers and other resources, covering many disciplines. Wanfang database is relatively small, mainly concentrated in academic journals and dissertations. Therefore, in terms of database coverage, China HowNet is strict.

2 Detection algorithm and rules: China HowNet adopts advanced semantic recognition technology, which can accurately detect the repeated parts of papers, and identify and process quotations and footnotes. However, Wanfang's duplicate checking is mainly based on the repetition of more than 10 words, and it is relatively weak in dealing with quotations, footnotes and other formats. Therefore, China HowNet is strict in detection algorithm and rules.

Accuracy of duplicate checking results: Due to the wide coverage of China HowNet database, the advanced semantic recognition technology can accurately detect the duplicate parts of the paper. However, Wanfang duplicate checking has some limitations in dealing with quotations and footnotes, which may lead to missed or false detection. Therefore, China Knowledge Network has strict requirements on the accuracy of duplicate checking results.

HowNet, VIP and Wanfang are the systems used by most schools, and their databases are authoritative. Paperfree and papertime are auxiliary revision references, which provide free weight checking, machine weight reduction, online revision and other functions, covering about 70% of HowNet's data, which can reduce the absolute cost of pre-test fees. To be on the safe side, it is recommended to use the duplicate checking system required by the school or institution for testing.