The thesis retrieval system of China's higher education literature guarantee system is the CALIS thesis center service system. According to relevant information, it is one of the three public service systems of China's higher education "2 1 1 Project", "Ninth Five-Year Plan" and "Tenth Five-Year Plan" approved by the State Council. The purpose of CALIS is to integrate national investment, modern library concept, advanced technical means, rich literature resources and human resources in colleges and universities under the leadership of the Ministry of Education, and to build a joint guarantee system for educational literature with China Higher Education Digital Library as the core, so as to realize the * * * construction, * * knowledge and * * enjoyment of information resources, give full play to the greatest social and economic benefits, and serve the cause of higher education in China.