上颌骨骨折中最具诊断意义的症状是() ["牙齿折断或移位","面部肿胀","上颌骨出现动度和错位","脑震荡","鼻腔出血"]
切牙舌向移动1mm需要间隙()。 ["2.5mm","3mm","2mm","1mm","1.5mm"]
在双缝干涉实验中,一钠灯发出的波长为589nm的光,在距双缝1.00m的屏上形成干涉图样。图样上相邻两明纹中心间距为0.350cm,则双缝的间距为() ["2.06×10-7m","2.06×10-4m","1.68×10-4m","1.68×10-3m"]
与继发龋发生无关的是() ["A.腐质未去净","B.洞形制备不良","C.材料调制不当","D.充填操作不当","E.未做窝洞消毒"]
茶碱的有效血药浓度范围正确的是() ["0-10μg/ml","15-30μg/ml","5-10μg/ml","10-20μg/ml","5-15μg/ml"]
什么是原发性脑损伤和继发性脑损伤?