1. Log in to CNKI and select the duplication checking tool. CNKI provides a variety of plagiarism checking tools, including "HowNet Journal Plagiarism Checking", "HowNet Master and Ph.D. Plagiarism Checking", etc.

2. Select the source of the paper to be checked for plagiarism. You can upload a paper you have written locally, or directly select relevant documents from the CNKI database for comparison. The broader the sources selected, the more accurate the plagiarism check results will be.

3. Wait for the duplication check results to be generated. The plagiarism check process generally takes from a few minutes to a few hours, depending on the length of the paper and the busyness of the database.

4. Check the duplication check report and make modifications. The plagiarism check report will show the duplication rate of the paper, the specific content of the duplication and the source of the citation. According to the prompts in the plagiarism check report, the author can modify the repeated parts in the paper to achieve the purpose of reducing weight.

The above is all about how to check plagiarism on CNKI. I hope it will be helpful to you!