GC-MS combined with AMDIS and Koáts retention index to investigate dynamic change rules of volatile components from Atractylodis Macrocephalae Rhizoma with different stir-baking degrees Study on composition of essential oils in three different origins‘ Curcumae Rhizoma by AMDIS and retention index Study on composition of essential oil in above-ground and root of Bupleurum malconense and root of B. chinense by AMDIS and retention index Comparative Analysis of Essential Oil Quality and Composition from Tissue Culture Seedlings of Thymus vulgaris L. Using Different Extraction Methods