The requirements of different institutions are different, and the academic year system is also different. It usually takes 2-3 years to graduate, but some colleges and majors require 4-5 years, depending on the level and number of papers you publish. If the published articles are of high level and large quantity, you can also apply for early graduation. Specifically, each college has different requirements for what level of articles should be published after doctoral graduation. For example, some schools only need one SCI or an authoritative article (some institutes of Chinese Academy of Sciences and some universities), but some schools require one SCI and two core or two SCIs, which is different.