Can I add two more papers after checking the duplicate?
You can't. After the paper is copied, you can't pass on the new one. After the paper is uploaded to HowNet for the first time, it will be included in the database of HowNet as a document resource, and the second upload will be rejected by the system. The repetition rate of the second paper is the same as that of the first paper, and the repetition rate is too large to upload to HowNet.