periodicallyadv.周期性地;定期地
periodicaln.期刊adj.定期的
periodicals of national level国家级期刊
periodical on library science图书馆学期刊
periodicals paper periodicals纸质期刊
periodical boundary condition周期性边界条件
periodical stirring ball mill周期式搅拌球磨机
periodical acquisitioning work期刊采访工作
periodical network publication期刊网络出版
periodical literature resource期刊信息资源