【摘要】 一条农牧分界线绵延于中国西北地区,由这里将中国分隔成两个不同的经济区域:农耕经济区与游牧经济区。这里也就成了农耕文明与游牧文明接触与碰撞的交汇点,从而使西北地区对历代中原王朝具有非常重要的边防与国家安全的意义。从周朝开始,历秦、汉、隋、唐,各中原王朝为保障自身安全,在西北地区开疆拓土,遂使这里成为汉唐都畿与历代中原王朝的安全屏障。可以说,西北繁荣与否关乎天下,而西北安危亦于天下安危有莫大之影响。更多还原

【Abstract】 A line that lies in northwest region of China divided the state into different economic regions :agricultural economic region and nomadic economic region. Being a joint place where agricultural civilization and nomadic civilization contacted and clached with each other, Northwest China had a vital influence on China’s border defence and state safety in every dynasty .For safety, every dynasty from Zhou to Han had enlarged their countries in northwest region where the safety were safeguarded. So, the safety and the prosperity of the northwest was closely related to the whole state.更多还原