1. Library: Library is the main way to obtain full-text documents, especially university libraries and public libraries. These libraries usually have a large number of electronic resources and paper resources, including various academic journals, papers, books and so on. Many libraries also provide online retrieval systems to facilitate users to find and obtain the required documents.

2. Academic database: The academic database is an online resource library, which contains a large number of academic journals, papers, conference papers, dissertations, etc. Common academic databases include CNKI (China Knowledge Network), Wan Fang data, VIP information, WebofScience, PubMed, IEEEXplore and so on. These databases usually require a paid subscription, but some university libraries may provide free access.

3.OpenAccess platform: Open access refers to the author's choice to provide free reading and use for the public when publishing academic papers. Open access platforms such as arXiv, BioRxiv and PLOSONE. Users can get a large number of full-text academic papers for free on these platforms.

You can try to contact the author of the document or his unit and ask them to provide the full text. Many authors will be willing to share their research results, especially academic research and academic exchanges.

5. Purchase or lease: For some documents that are very rare or need to be preserved for a long time, you can consider buying or renting paper versions. In addition, some databases also provide a single paid download service, and users can purchase the full text of the required literature as needed.

6. Document mutual assistance platform: Some websites or forums provide document mutual assistance services, and users can post help information on these platforms and seek help from other users to download or provide full-text documents. However, it should be noted that this method may have copyright risks and should be used with caution.