“national primary frequency standard”的概念、定义、翻译、参考文献-科学参考

单词	national primary frequency standard
释义	national primary frequency standard Encyclopedia 工学频率标准释 national primary frequency standard秒长国家计量基准直接复现秒定义的实验装置。输出的标准频率具有最高计量学特性，作为统一全国秒长量值（频率量值）最高依据的计量器具，全国只有一套。
随便看	road traffic and transportation road traffic control road traffic demand forecast road traffic emergency rescue system road traffic injury road traffic injury prevention road traffic law and regulations road traffic law enforcement road traffic management road traffic marking road traffic offenses management information system road traffic organization Road Traffic Safety Association of China Road Traffic Safety Association of the People's Republic of China road traffic safety early-warning road traffic safety enforcement road traffic safety information system road traffic safety preparedness road traffic safety publicity road traffic security road traffic sign road traffic signal controller road traffic signals road traffic system road transit online ticketing

科学参考收录了854744条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。