periodicles期刊periodicadj.周期的；定期的；间歇的；完句的periodic coeffcients周期系数periodic maintenance定期维修periodic peritonitis周期性腹膜炎periodic fluctuation周期性波动periodic instability周期性不稳定性periodic sign series周期符号级数periodic attenuation周期衰减periodic shape error周期性形状误差periodic phase state周期相态periodic examination定期检定