装置停工检修时,除焦工应做好哪些工作?
宿主为rec,可在噬菌体溶源性细菌中鉴别重组合非重组入噬菌体的条件为() ["redgame基因存在","redgame基因缺失,无chi位点","redgame基因缺失或替换,且有chi位点","redgame基因存在且无chi位点"]
制造费用是指生产过程中发生的()。 ["间接生产费用","间接计入费用","应计入产品成本的各项生产费用","应计入产品成本,未专设成本项目的各项生产费用"]
煤的形成需要合适的气候条件,它们是() ["炎热气候","潮湿气候","暖湿气候","干燥气候"]
质粒PSC101带有何种抗性基因() ["卡那霉素抗性基因","四环素抗性基因","青霉素抗性基因","链霉素抗性基因"]
焦炭塔大吹汽放空阀打不开时应如何处理?