Study on the etiquette system of emperor's activities in Tang Dynasty 并列题名：Study on the etiquette system of emperor's activities in Tang Dynasty Study on legal system of commercial tax in Ming dynasty Study on system of prime minister in Song dynasty Study on the buddhist state monasteries of Tang dynasty Study on the land tax system and related problems in Song dynasty Study of the biographies of empresses and concubines in the Tang dynasty Study on the assessment of the civil officials in Qing dynasty Study on the marching system of the Tang Dynasty Study on the tributes and its system in Qing dynasty