Dissertations are usually not classified as periodical documents. Dissertation is an academic document written by graduate students after completing their academic research and passing the degree evaluation procedure. This paper aims to show the independent research ability and academic works of graduate students.

Dissertations are different from periodical papers, which are the research results published by researchers or scholars in specific academic journals. Periodical articles go through a rigorous peer review and editing process to ensure their quality and academic reliability. Journal articles are widely recognized and cited for academic research, academic exchange and knowledge dissemination.

Although dissertations also contain research contents and achievements, they are usually not regarded as periodical documents. Dissertation mainly meets the requirements of academic evaluation and degree, and does not pursue extensive academic dissemination and citation. Dissertations are usually stored in the libraries or dissertations databases of academic institutions for further study and reference by scholars and researchers.

However, some dissertations may be expanded into journal articles or other forms of publications in the subsequent academic work, and further accepted by peer review and editing. Such an article may contain part or all of the contents of the dissertation, and be revised and updated as necessary, and published in academic journals through peer review.

Generally speaking, dissertations and periodical literature are different in purpose, publishing channels and academic recognition. Dissertations are mainly academic documents written to meet the requirements of academic degrees, while periodical documents are independent and peer-reviewed research results, which are used to exchange and spread knowledge in academic circles.