电子天平显示“+E”时,超载所致的故障修理方法是() ["检修电子天平的主板故障并排除","正确调整限位螺母位置","减少质量,保证在最大载荷内称量","检修或更换电子天平的加力线圈"]
臀部伤口,位置较深,出血量较多,应选用() ["包扎止血法","加压包扎止血法","加垫屈肢止血法","填塞止血法","止血带止血法"]
黄铜
苯是一种常见的工业毒物,主要通过() ["食道","皮肤","呼吸道","消化道"]
下列哪项不是文献的外部特征?() ["著者","标题","来源","分类号"]
简述发病率和时点患病率的区别。