adjective · the nine schools of thought, philosophical schools of the Spring and Autumn and Warring States Periods (770-220 BC), viz Confucians, Daoists, Yin and Yang, Legalists, Logicians, Mohists, Diplomats, Miscellaneous, and Agriculturalists

他在学术研究中深入探讨了先秦时期的九流思想。