What reliable websites are there to check duplicate papers?

Here are some reliable websites for duplicate checking of papers:

-China HowNet: Most journals and professional duplicate checking websites recognized by schools charge relatively high fees.

-VIP: database of well-known academic journals in China, providing duplicate checking service for papers free of charge.

-Wanfang: a database of well-known academic journals in China, which provides duplicate checking services for papers free of charge.

-PaperPP: a professional free paper duplicate checking website, which supports multilingual duplicate checking.

-PaperGood: a professional free paper duplicate checking website, which supports multilingual duplicate checking.

-PaperQuery: a professional free paper duplicate checking website, which supports multilingual duplicate checking.