quadratic equationquadrupolequalitativequalitative analysisqualitative dataquality controlquantquantaquantitativequantitative analysisquantum mechanicsquantum numberquantum of actionquantum opticquantum phonomenonquantum statequantum statisticsquantum theoryquantum theory of valencequantum wave equationquantum yieldquartzquasi atomquasi crystalquasi cyclicquasi elastic forcequasi ellipticquasi free electron theoryquasi inversequasi linear equationquasi moleculequasi stable elementry particlequasi stationary statequasichemicalquasiparticlequenching reactionquicksilverquinhydronequinolquinolidinequinolinequinonequinoniminequintetquuartet