Dissertations are divided into three levels: bachelor's thesis, master's thesis and doctoral thesis. Among them, the quality of doctoral thesis is the highest, and the doctor has experienced a longer period of study and accumulation, and his knowledge is more profound, so the articles written naturally have higher gold content. Dissertation refers to a research report or scientific paper written in order to obtain a certain degree. Dissertation refers to a paper that must be written to a certain extent, and there are strict requirements on the format. Paper is a form of academic paper.