1. Paper retrieval: Paper carrier is the main form of patent literature and the main object of retrieval. Generally, the materials retrieved by paper retrieval are the least prone to errors and the most evidential, but in the process of patent retrieval, it is inefficient, time-consuming and laborious, and easy to be lost and damaged. In addition, due to the long printing and distribution cycle, it is difficult to retrieve the latest materials.
2. Software retrieval: Software retrieval usually includes microfilm, computer magnetic media and CD-ROM patent literature retrieval. With the development and popularization of computer technology, CD-ROM database has played an important role in patent retrieval and patent full-text acquisition. Although CD retrieval is fast, the limited enjoyment of CD retrieval limits its application scope and the speed of updating is limited.
3. Online search: fast, new in content, but without legal effect. If it is to be used as evidence, the relevant departments need to show the corresponding certificates, or the legally recognized departments need to search and download the certificates.