核酸基本组成单位间的连接键主要是（） ["肽键","磷酸二酯键","氢键","疏水键","二硫键"]
大多数阻塞性睡眠呼吸暂停低通气综合征患者睡眠中猝死主要是因为（） ["脑缺氧","心律失常","呼吸性酸中毒","低氧血症","高血压"]
患儿，8岁。全身高度浮肿，下肢肿甚，按之深陷难起，面色晄白，神倦乏力，脘腹闷胀，大便溏，小便少，舌淡胖，苔白，脉沉细。其治法是（） ["健脾益气，利水消肿","温肾健脾，化气行水","滋阴补肾，清热利湿","化湿泄浊，利气行水","补益脾肺，宣肺利水"]
腹股沟疝检查时，压迫内环的部位应在（） ["腹股沟韧带中点","耻骨结节外侧","肿块隆起最明显处","腹股沟韧带中点上方2cm","精索的前内方"]
蛋白质定量的方法有（） ["双缩脲法","Folin酚试剂法","紫外吸收法","凯氏定氮法","以上均可"]
简述环甲膜穿刺术。
