三级、四级实验室
the third and Fourth level laboratories
八名局长级官员
eight director-level officials
局长级官员
directorate grade officers
变步长四步换流策略
validity of varying-step four steps communication strategy
不等长四相扩频序列
4-phase spreading sequence with inequal length
超高效液相色谱串联三级四极杆质谱
UPLC-triple quadrupole MS
超高效液相色谱—串联四级杆质谱
ultra performance liquid chromatography-tandem mass spectrometry
ultra performance liquid chromatography-tandem quadrupole mass spectrometry
串联四级杆质谱
tandem quadrupole mass spectrometry
QQ-TOF mass spectrometry