骨干gǔgàn 1.长骨的中央部分,两端跟骨骺相连,里面是空腔。{diaphysis; shaft of a long bone with a cavity, linked with the epiphysis at both ends;} 2.〈比喻fig.〉在总体中起主要作用的人或事物{backbone; mainstay}: ～分子{core member; key member; key element}|～企业{key enterprise}|业务～。{key member of a professional or business staff; backbone; mainstay}