Paper duplication checking refers to comparing the paper with the documents in the database, and checking whether there is plagiarism, duplication or improper citation in the paper. Paper duplication checking mainly focuses on the repetition rate of papers, that is, the proportion of the parts identified as duplicates in the whole paper. Cnkitime's free website for duplicate checking of academic misconduct papers, undergraduate edition (final graduation thesis), graduate edition (final graduation thesis) and periodical title edition (periodical submission and title evaluation) can all be used for duplicate checking.