Research on the development issues of apartments for the elderly in China Research on the development of coarse grain industry in China Research on the development of alfalfa industry in China Research on the development of dairy industry in China Research on the development of regional growth pole in China Research on the development of tourism service trade in China Research on the coordinated development of educational resources for the elderly in China Research on the development measures of digital economy in the era of big data Research on the development of digital creative industry in China Research on the development of fishing port economic zone in China