1, common law
It is a method of literature retrieval by using literature catalogue, abstract, index and other retrieval tools. The key to using this method is to be familiar with the nature, characteristics and retrieval process of various retrieval tools and search from different angles. Common law can be divided into sequential inspection method and backward inspection method.
2, backtracking method
This is a method of continuously tracking and searching the references attached to the existing literature. In the case of no retrieval tools or incomplete retrieval tools, this method can obtain highly targeted information with high precision and low recall rate.
3. Segmentation method
It is a combination of retrospective method and common law, and the two methods are used alternately in stages and segments until the required information is found.