Social security system for labors in the period of Nanjing national government 并列题名：Social security system for labors in the period of Nanjing national government Trial system during the period of Nanjing na-tionalist government 并列题名：Trial system during the period of Nanjing na-tionalist government a study on the northwest economic development during the period of Nanjing national government Study on the reform of salt administration of Nanking national government