题型:填空题 二十五岁女性,1天前,口腔剧烈疼痛,进食困难;手背及下肢对称出现水疱,疼痛剧烈,去年春季节出现过类似病损。查体:口腔内大面积糜烂,覆盖较厚的灰白色假膜,手背及下肢皮肤可见对称性水疱,周缘充血,可见虹膜状红斑 。若不给予药物治疗,多长时间可自愈 ()A.1~3天 B.2~4周 C.5~7天 D.1~2个月 E.2~3个月 查看答案
题型:填空题 It is global warming, rather than other factors, _______ the extreme weather. A that have led to B which has caused C which are causing D that has led to 查看答案
题型:填空题 有一个关系:学生(学号,姓名,系别),规定学号的值域是8个数字组成的字符串,这一规则属于________。A.实体完整性约束B.参照完整性约束C.用户自定义完整性约束D.关键字完整性约束 查看答案