“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	logic of vagueness logico-mathematical calculus logico-mathematical language logico-mathematical model logic operation logic predicate logic probe logic probe indicator logic programming logic programming language logic quantifier logic recovery methods and techniques logic representation logics for artificial intelligence logics in computer science logic state analyzer logic testing logic test pen logic timing analyzer logic unit logic valence logic verification system logic with equality logic without equality log-in

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。