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 analysis.

2.Grammarly: Grammarly is a powerful online grammar and spelling checking tool, which can also be used for double checking. It can detect duplicate content in text and provide suggestions and modifications.

3.Copyscape: Copyscape is a tool specially used to detect the repetition rate of web content. Can help users find out whether there is something similar to their own articles on the Internet.

4.Plagscan: Plagscan is a professional duplicate checking software, which can detect the similarity of texts and provide detailed reports and analysis. It is widely used in academic and commercial fields.

5.Viper:Viper is a free online duplicate checking tool, which can detect the similarity of texts and provide simple reports. Suitable for individual users and small teams.

6.Quetext: Quetext is a free online duplicate checking tool, which can detect the similarity of texts and provide detailed reports and analysis. It supports a variety of file formats, including Word, PDF and Web pages.

7.PaperRater: PaperRater is a free online duplicate checking tool, which can detect the similarity of texts and provide simple reports. It also provides functions such as grammar and spell checking.

These websites are accurate and reliable, but it is best to know their characteristics and limitations before using them and choose the appropriate tools according to your own needs. In addition, we should also pay attention to the protection of personal privacy and copyright issues and abide by relevant laws and regulations.