The nature of the subject is what kind of problem the scientific research subject belongs to. There are three classifications: 1, which are classified according to the research process: scientific research topics are theoretical research, applied research and development research. 2. According to research methods, scientific research topics include experimental research, investigation research and observation research. 3. According to the risk classification of researchers: Research topics are divided into exploratory research and development research.

The topic is a problem that needs to be studied and solved, so the background of the topic is under what circumstances and conditions the problem occurred and what is the significance of the topic research. Topics include municipal topics, provincial topics and national topics. The nature of the subject is what kind of problem the scientific research subject belongs to.