Theoretical and empirical study of teachers' sense of gain 并列题名:Theoretical and empirical study of teachers' sense of gain theoretical and empirical study of the Pearl River Delta region Theoretical and empirical study on the power list system Theoretical and empirical study on backpacker tourism Theoretical and empirical study of family farm development theoretical and empirical study based on Chinese market Theoretical and empirical study on the governance of commercial banks Theoretical and empirical study on cyclical company valuation a theoretical and empirical study of food safety regulation in China