溶解游离亲脂性生物碱的最好溶剂是() ["水","甲醇","正丁醇","氯仿","乙醇"]
我国水轮机主轴直径大雨()mm时,采用薄壁轴。 ["A、300 ","B、500 ","C、600 ","D、400"]
固体吸附剂采样管的最大采样体积越大,浓缩效率() ["越小","不确定","与最大采样体积无关","越大","不变"]
生物碱沉淀反应的条件是() ["酸性水溶液","碱性水溶液","中性水溶液","盐水溶液","醇水溶液"]
测定Cu2+时,加入氨水作显色剂,生成兰色铜络离子〔Cu(NH3)4〕2+应选择的滤光片是:()。 ["橙红色","黄绿色","黄色","红色"]
图书馆学研究中的一般科学方法有哪些?