Qualitative Recognition on Omitted Ingredients in Liuwei Dihuang Pills by Bayesian Analysis and PRIMA Determination of loganin and paeonol in Liuwei Dihuang pills by HPLC amalgamated of double UV waves Rapid determination of loganin in Liuwei Dihuang Pills by NIR spectroscopy HPLC Fingerprint and chemical pattern recognition of Liuwei Dihuang Pills Study on reference extract solution of Liuwei Dihuang Pills