The number of centers in a multicenter clinical trial is at least several

3. Multicenter clinical trial refers to the same clinical trial protocol, in more than three (including three) clinical trial institutions to implement the clinical trial can accelerate the process of clinical trials, to ensure that the collection of materials more representative, to enhance the richness of the trial basis and credibility is useful to learn from the best, to learn from the best, and to improve the design of the clinical trial, the conduct of clinical trials, and the standard of the results of the presentation.