1. School Library: Many universities and research institutions have their own libraries, through which students and researchers can obtain many excellent academic journals and full-text papers.

2. Academic search engines: Search engines such as Google Academic, China HowNet, wanfang data and PubMed provide a large number of full-text download services for academic papers and periodicals, and most of them are free.

3. Full-text databases: such as China HowNet, Wan Fang Data, springerlink, ScienceDirect and JSTOR. These databases contain a large number of periodicals, papers and works, and the full text of the papers can only be obtained through subscription, membership or purchase services.

4. Academic exchange websites: such as ResearchGate and Academia.edu. These websites are platforms for scholars to share and exchange academic research results, and many academic papers can be obtained on these websites.

5. Requirements for the author or publishing house: contact the author or publishing house by mail or letter to ask whether the full text can be obtained, and sometimes the authorization of the author or publishing house may be required.

6. Purchasing papers: Some periodicals and publishing houses provide paper purchasing services, and the full text of papers can be purchased through these platforms.

7. Reference search: By investigating the references in other papers on similar topics, you may be able to find the links or quotations of the papers you need.

The way to obtain the full text of the paper needs to pay attention to the following points:

1. Copyright issues: Pay attention to copyright issues when downloading and using papers to ensure the right to use papers.

2. Credibility: Choose databases, academic search engines and academic exchange websites with high credibility, and avoid using some fake websites or paper download platforms to avoid downloading false, wrong, misleading or unreliable papers.

3. Fees: Some sources or platforms may need fees, such as purchase, membership or subscription. You need to pay attention to your economic ability and needs, choose the platform that suits you and pay the corresponding fees.

4. Search skills: You need to master the search skills of various databases and academic search engines in order to search the papers you need quickly and accurately.

5. Apply for authorization: Some authors or publishers may need authorization to use the full text of their papers, and they need to politely apply for authorization in emails or letters to obtain the right to use them.

6. Citation retrieval: To find references and citations of existing papers through citation retrieval, attention should be paid to the selection of citation retrieval tools or platforms.