清朝康熙、乾隆年间，奠定了统一的多民族国家的疆域。那时，东北以绵亘数千里的外兴安岭为界，北至萨彦岭，西北有周围数百里的巴尔喀什湖，西南至伊洛瓦底江中上游，南有西沙群岛和南沙群岛，乐有库页岛和钓鱼岛列岛等众多岛屿，幅员辽阔广大。但是鸦片战争以后，中国逐渐沦 During the reign of Kangxi and Qianlong in the Qing Dynasty, the territory of a unified multi-ethnic country was laid. At that time, the northeast stretches thousands of miles outside the Anning Mountains, north to Sayan Ridge, northwest surrounded by hundreds of miles of Lake Balkhashi, southwest to the Irrawaddy middle and upper reaches, the south of the Xisha Islands and the Nansha Islands, Island and the Diaoyu Islands Island and many other islands, vast and vast. However, after the Opium War, China gradually reduced