【多选题】领队带领旅游团在境外海关退税处办理退税手续时,应告知旅游者出示( )。
【单选题】在DC内,抗原肽与MHCⅡ类分子结合的部位是
【简答题】Most of us drink soda. Even if we know soft drinks are bad for the health. I think we need to know more about this drink that we love so much. And here are five reasons why we drink soda: The taste co...
【单选题】能与MHCⅡ类分子结合的细胞分化抗原是()
【判断题】长形数据转化为宽型数据时必须指定索引变量,区分个案。