①: Library (online)

The library has purchased a large number of periodicals and thesis databases, mainly school libraries and provincial libraries.

②: Online periodical papers database.

For example, Wanfang, China Knowledge Network and National Science and Technology Documentation Center (nstl).

③: Search by search engine.

Try to search: free papers, or add a search keyword, such as file type: pdf.

PS: Those so-called free paper websites are actually written by papers.

It's better to find yourself some pieces to put together. ...