Research on news legal system in the period of Beiyang Government Research on postal system during the period of Beiyang government (1912-1928) 并列题名：Research on postal system during the period of Beiyang government (1912-1928) Research on the water policy of Jingzhao-Zhili in the period of Beiyang government 并列题名：Research on the water policy of Jingzhao-Zhili in the period of Beiyang government Research of the graduates' employment in the period of National Government Research on the legal system in China's new era of innovative development Research on the legal system of government procurement research on the legal regulation with responsible government research on the procuratorial system of the Nanking National Government