The most common is the school library. There are many books in the library, and there are many paper documents in them. When we need to write a paper, we can go through the library. This is a good method. If the school library is not enough, we can also go to the nearby city library, where there are many books. When we manually check the library, we can also make full use of the electronic reading room, which contains a lot of electronic resources, and it is convenient to search and download relevant materials. But if the above two items are not enough, we can have a third method. We can also get the literature database of some papers by searching some documents on the Internet. We use Wanfang Database for many papers, and many classics can be found in it. We also include international sci-tech journals of basic disciplines and other disciplines, papers published in engineering fields and conferences, international conferences and so on. China HowNet is also commonly used, and its biggest feature is that it can directly obtain the original text. Directional access to the original text, the search effect is very good and fast, like English databases, such as Elsever SDS, a multinational publishing company with a long history in the Netherlands, which contains many journals, all of which are internationally recognized authoritative large-scale retrieval databases and core academic journals in various disciplines.