气态液化石油气比空气轻,泄漏入空气后,一般先沉积在地面上。
下列关于T波的描述错误的是() ["代表心室快速复极时的电位改变","是一不对称宽大而光滑的波形","方向与QRS波群主波方向一致","T波电压不应低于同导联R波的1\/10","T波时间不能超过0.21"]
临床症状和影像形态学诊断为原发性肝细胞癌患者,血清动态观察试验指标首选() ["Alb测定","AFP测定","总蛋白测定","BUN测定","LDH测定"]
治疗以促进宫缩为主() ["协调性宫缩乏力","不协调性宫缩乏力","协调性宫缩过强","子宫痉挛性狭窄环","病理性缩复环"]
MorbizⅡ型房室传导阻滞的特点是() ["P-R间期恒定,部分P波后无QRS波群","P-R间期逐渐延长,直至一个P波后漏脱一个QRS波群,周而复始","P-R间期逐渐延长","P波与QRS波群毫无相关性","P波增宽>0.11"]
叙述如何选择电火花电极材料?