When searching for documents, we can start with Chinese documents. Commonly used are China HowNet, VIP and Wanfang. Some documents are available in most databases, and some documents may only be available in some databases. When we can't find the document, changing the database is also a method (take HowNet as an example).

After entering HowNet, you can find advanced search in the search box. It is difficult to find the literature you really want with a search keyword.

After entering the advanced search, you can search by title, keywords, etc. At the beginning of the search, you can choose a key keyword related to your own project as the starting point to see the development direction of current research. It is best to search in titles, keywords and abstracts, because the scope of the full text is too large, and it is likely to be too different from what is needed.

At the same time, you can customize multiple related or unrelated keywords, and "including", "including" and "not including" can filter data well.

If you want to further narrow the search scope or search for other contents, you can click "+"to add, and the number of documents will be further reduced.

Next, we can further limit the release time of documents and other factors.

If there is no limit to the publishing time when searching, you can browse and sort in groups after searching.

The above are the basic methods of literature retrieval.