On-campus duplicate checking: Many university libraries can duplicate papers, and generally use the paper duplicate checking system cooperated by schools, such as HowNet.

Duplicate check of a treasure: Search for "duplicate check of papers" on a treasure, and you can find many businesses that provide duplicate check services for papers, such as paperfree. Pay attention to comparing prices and scores when choosing, and try to choose reputable old shops and businesses.

Paper duplicate checking website: You can directly search for the keyword "paper duplicate checking" on the search engine to find the duplicate checking system, but the duplicate checking website found in this way may not be reliable. It is best to go directly to the duplicate checking website recommended by others or the website you are familiar with.

It should be noted that the security of papers should be ensured when these methods are used for duplicate checking.