Research of derivatives usage of China listed companies 并列题名：Research of derivatives usage of China listed companies Research on debt maturity structure of Chinese listed companies Research on share swap merger of China's listed companies Research report on esg of Chinese listed companies 并列题名：Research on debt maturity structure of Chinese listed companies Research on risk information disclosure of Chinese listed companies Research report on ESG of Chinese listed companies Research on M&A performance of Chinese listed companies Research on earnings management of listed companies