Study on structure-activity relationship of flavonoids’ multidrug resistance-associated protein inhibitory activity QSAR modeling for LC50 of organic chemicals to rainbow trout using molecular connection index 3D QSAR Studies on Cytotoxin Actives of Ent- kauranoids from Isodon xerophilus ( Labiatae) by CoMFA Study on transmission rate and quantitative structure-property relationships of alkaloids and iridoid compounds on UF membranes with MWCOS of 1 000