基地式调节阀适用于()的场合。 ["A、流量变化大;","B、调节精度要求不高;","C、仪表气源供应方便;","D、调节精度要求高。"]
对伴胸痛的无痰性干咳宜选用() ["A.氯化胺","B.咳必清","C.可待因","D.必嗽平"]
航进中的船舶舵力受到伴流和螺旋桨排出流的影响,它是:() ["伴流和排出流都提高了舵力","伴流与排出流都降低了舵力","伴流使舵力增强,排出流使舵力下降","伴流使舵力下降,排出流使舵力增强"]
下列何药禁用于支气管哮喘() ["A.肾上腺素","B.异丙肾上腺素","C.普萘洛尔","D.氨茶碱"]
选择性β2受体平喘药() ["A.氨茶碱","B.沙丁胺醇","C.异丙肾上腺素","D.色甘酸钠"]
炼油厂典型的原油三段汽化蒸馏装置除汽提塔外还有三个塔,即()、()和()。