The National Natural Science Foundation of China cannot be used for in-service doctoral tuition expenses. According to relevant public information, "Natural Science Fund" refers to the fund projects established by various countries to encourage the innovation and development of natural science. Famous ones include the National Natural Science Foundation of China, the National Science Foundation of the United States, the Irish Science Foundation, the Czech Science Foundation and the European Science Foundation. In China, it generally refers to the National Natural Science Foundation. In addition, provinces and regions often set up natural science funds at corresponding levels.