NiuDown is a document vertical search service from China (similar to the Baihui previously introduced), it focuses on Doc, Exl, PPT and PDF document search, and the search results of the files have a direct download address. Personally feel that this service is not bad, it does bring a lot of convenience, but it is likely to infringe on others' privacy and copyright, for example, if I use resume as a keyword to search, I can find a lot of other people's resume documents.