What are the basic methods to find literature?

① direct method, ② direct method, ③ backward method, ④ spot check method, ⑤ retrospective method, and ⑤ circulation method.

① Direct method

Also known as ordinary method, it refers to the method of directly using retrieval system (tool) to retrieve literature information. It is also divided into sequential investigation, reverse investigation and spot check.

② Follow-up methods

Sequential retrieval method refers to the method of using retrieval system to retrieve literature information from far to near in time sequence. This method can collect systematic documents of a certain discipline and is suitable for document retrieval of larger disciplines. For example, if we know the initial age of a subject and need to know the whole process of its development, we can use the sequential search method to search from the initial age.

③ Backward search method

Reverse search method is a kind of literature retrieval method which uses retrieval tools from near to far, from new to old, and relative to time. Using this method, you can get the latest information as soon as possible.

④ Spot check method

Spot check method refers to the characteristics of the project, selects the most likely or most likely time period of document information related to the project, and uses retrieval tools to carry out key retrieval.

⑤ retrospective method

It refers to the method of tracing the original texts (cited documents) one by one without using the general retrieval system, and then expanding the scope of literature information one by one from the list of references listed after these original texts, and tracing them one by one. It can snowball and get better retrieval results according to the citation relationship between documents.

⑥ Cycle method

Also called subsection method or synthesis method. It uses direct method and backtracking method alternately in stages to learn from each other's strong points and cooperate with each other to obtain better retrieval results.