1. Study on the Long-term Continuation of China Feudal Society. 2. The long-term continuation of China's traditional political system and feudal society. 3. China's ancient economic structure and the long-term continuation of feudal society. 4. China's systematic cultural consciousness and the long-term continuation of feudal society. 5. Research on the germination of capitalism. 6. Study on the reasons and nature of the development of ancient commodity economy in China. 7. Study on the characteristics and level of ancient commodity economy in China. 8. Study on individual small-scale peasant economy and the social nature of ancient China. 9. Changes of ecological environment in northern China in historical period and their causes. 10, research on the policy of emphasizing agriculture and restraining business. 1 1, the economic region in the Warring States, Qin and Han Dynasties. 12, commodity economy and social changes in the Warring States, Qin and Han Dynasties. 13 comparative study on the policies of emphasizing agriculture and restraining commerce in Qin and Han dynasties. 14, a review of economic policies in the Western Han Dynasty. 15, Haozu and the society of Han Dynasty. 16, Study on Land System in Han Dynasty. 17, Migration in Qin and Han Dynasties 19, Development and influence of Confucianism in Han Dynasty. 20, the reasons for the formation of gate politics. 2 1, gentry and the development of Wei and Jin culture. 22. Scholars and society in Wei, Jin, Sui and Tang Dynasties. The development of Jiangnan economy and the shift of economic center of gravity during the Six Dynasties. 24, officers and men system and Guanlong Group. 25. Commodity economy and social changes in Tang and Song Dynasties. 26. The development of commodity economy in Tang and Song Dynasties and its historical influence. 27. The imperial examination system and the society in Tang and Song Dynasties. 28. Economic policies and social economy in the Tang and Song Dynasties. 29. Research on the similarities and differences of foreign policies in Han and Tang Dynasties. 30. Research on local power in Sui and Tang Dynasties. 3 1, local administrative system and the long-term division of Wei, Jin, Southern and Northern Dynasties. 32. Door valve group and politics in Sui and Tang Dynasties. 33. Cities and urban economy in Tang and Song Dynasties. 34. The ancient prose movement and the revival of Confucianism. 35. Buddhism and Tang and Song culture. 36. Taoism and Tang and Song culture. 37. Research on cultural policies in Yuan Dynasty. 38. The provincial system and local development in Yuan Dynasty. 39. The economic policy of the Ming Dynasty and its historical influence. 40. Zhu Yuanzhang and politics in the early Ming Dynasty. 4 1, Refugees in Ming and Qing Dynasties and Mountain Development. 42. Commodity economy and capitalism in Ming and Qing Dynasties. 43. The development of frontier areas in Qing Dynasty. 44. State, society and water conservancy before the Tang Dynasty. 45. State, society and water conservancy after the Song Dynasty. 46. Local administration and social control in Qin, Han, Sui and Tang Dynasties. 47. Local administration and social control in Song, Ming and Qing Dynasties. 48. Scholar-bureaucrat class and social studies in Song and Ming Dynasties. 49. The political study of the landlord class and the China system. 50. Research on science and technology, society and culture in Tang and Song Dynasties. 5 1, Shaanxi during the Han and Tang Dynasties. 52. Shaanxi during the Song and Ming Dynasties. 53. Rural society in Han and Tang Dynasties. 54. Song and Ming rural society. 1. Immigration policy in Qin and Han Dynasties and its influence II. A review of the Qin and Han wars III. The development of northern frontier in Qin and Han dynasties and its historical significance. The development of northern frontier in Qin and Han dynasties and its influence on ecological environment 5. The historical role of China's ancient policy of attaching importance to agriculture. Discussion on commercial policy in western han dynasty. On agricultural policy in han dynasty. The population flow between Han and Hungary and its influence. Comment on the policy of the Eastern Han Dynasty towards the southern Xiongnu 10. On Sima Qian's view of state, 1 1. On the formation of consorts group in han dynasty. On social problems in the late Western Han Dynasty, 14. Characteristics of gentry in the Southern and Northern Dynasties, 15. On the ethnic policy of Emperor Taizong, 16. On the dual-track administrative system in Liao Dynasty 19. The formation and historical significance of the confrontation pattern between Song and Liao Dynasties. Reasons for the outbreak of the Song and Jin Wars 2 1. Redundant officials in song dynasty and their social influence 22. Jin dynasty's policy of attaching importance to agriculture. Cultural characteristics of yuan dynasty. Social life in the Western Han Dynasty reflected in Salt and Iron Theory. Disaster relief policy in the eastern han dynasty. The change of natural environment and the division of sixteen countries.