HowNet can import documents. First, users need to log in to the HowNet research interface. After logging in, click Learning and Learning on the left side of the page, click New My Topic and fill in the title. After creation, click the local upload button. Users can import the documents from the computer into the HowNet research platform, select the document type, and fill in the document title, author, keywords, abstract and other information. At the bottom, it is not mandatory to fill in the release time, source and place. Click OK when you are finished.

You don't need to delete references when you repeat the search. The purpose of doing this is to reflect the real scientific basis. It embodies a serious scientific attitude; Distinguish one's own views or achievements from those of others; In order to show respect for the scientific achievements of predecessors, and also to indicate the source of the cited materials for easy retrieval. Moreover, when the search of HowNet is repeated, adding references can also help students effectively detect whether the citation format is wrong, and students do not need to delete references when searching repeatedly.