First of all, from the purpose, academic papers are mainly published in academic journals to promote the development of disciplines and exchange academic views. Dissertation is to get a degree, which usually needs to be completed by defense.
Secondly, from the content point of view, academic papers usually focus on a specific research problem and need to have clear research objectives, methods and achievements. The dissertation needs to fully demonstrate the knowledge and ability of graduate students in the process of learning and research, including literature review, theoretical framework, research methods, data analysis and conclusions.
Furthermore, from the structural point of view, academic papers usually follow the structure of "introduction-method-result-discussion", emphasizing logic and organization. Thesis needs to contain more parts, such as abstract, table of contents, thanks, references and so on. And their structures are more complicated.
Finally, from the format point of view, academic papers need to follow the format requirements of journals, such as word limit and citation format. Thesis should follow the format requirements of the school or college, such as page limit and font size.
Generally speaking, academic papers and dissertations are both important forms of academic research, but the emphasis and requirements are different. Academic papers pay more attention to the innovation and academic value of research, while dissertations pay more attention to the overall ability and systematicness of graduate students.