Fiatarone M A,et al.The effect of exercise on natural killer cell activity in yong and old subjects.J.Gerontol.1989; 44:M37.是什么意思_Fiatarone M A,et al.The effect of exercise on natural killer cell activity in yong and old subjects.J.Gerontol.1989; 44:M37.在线翻译_英语_读音_用法_例句