Paper duplication checking is a very important part of academic research, which can help the author to ensure the originality and academic integrity of his research results. At present, there are many practical tools for paper duplicate checking. The following are some common tools for paper double checking:

1.Turnitin: Turnitin is the world's leading platform for testing academic integrity and originality, which is widely used in academia and educational institutions. It can detect the similarity of texts and provide detailed reports and feedback to help authors find and correct plagiarism.

2.Grammarly: Grammarly is a widely used English grammar and spelling checking tool, and it also provides a duplicate checking function for papers. It can detect the repeated content in the text and provide suggestions and modifications to help the author improve the quality and originality of the paper.

3.Copyscape: Copyscape is a tool specially used to detect the repetition rate of web content, and can also be used to check the repetition of papers. It can search the content on the Internet and generate detailed reports showing which parts are similar to other web pages.

4.Plagscan: Plagscan is a professional paper duplicate checking tool, which is widely used in academic circles and research institutions. It can detect the similarity of texts and provide detailed reports and feedback to help authors find and correct plagiarism.

5.Viper:Viper is a free online paper duplicate checking tool, which can detect text similarity and provide detailed reports and feedback. It supports a variety of file formats, including Word, PDF and Web pages.

These paper duplicate checking tools all have their own characteristics and advantages. Choosing the right tools can improve the quality and originality of the paper. When using these tools, authors should pay attention to the principle of academic integrity and avoid plagiarism.