Which website can compare European patents with American patents?

Patents protect their exclusivity by law in exchange for patent disclosure, so all patents that pass the examination should be made public, in other words, they can be downloaded from patent websites.

The websites of the European Patent Office (www.european-patent-office.org) and the United States Patent and Trademark Office (www.uspto.gov) can find their own related patents.

Ep.espacenet.com can find European patents, American patents and world patents filed in Europe.

Whether there is a Chinese version depends on whether the specific patent has been applied in China. If you apply for a patent in China, you can find the Chinese version on China National Intellectual Property Administration's website.