“System of four ethnic classes”的概念、定义、翻译、参考文献-科学参考

单词	System of four ethnic classes
释义	System of four ethnic classes Encyclopedia 历史学[政治制度]释 System of four ethnic classes四等人制中国元朝的民族等级制度。
随便看	ultrastrength material ultrastrong ultrastrong dual ultrastrong operator topology ultrastrong topology ultrastructural pathology ultrastructure ultra-supercritical power generation technology ultra telephoto lens, super telephoto lens ultra-telescopic meteor ultratelescopic meteor ultrathin film ultra-thin overlay ultrathin section ultra trace ultratrace analysis ultravacuum ultraviolation ultra-violet ultraviolet ultraviolet absorber Ultraviolet absorbing filter ultraviolet absorption detector ultraviolet absorption spectrum ultraviolet and visible spectrophotometer

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。