“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	pyralid moths Pyramid pyramid pyramidal antenna pyramidal cell pyramidal eminence pyramidal error pyramidal frustum pyramidal inversion pyramidalis pyramidal layer pyramidal neuron pyramidal number pyramidal plane pyramidal surface pyramidal tract pyramid building pyramid of biomass pyramid of energy Pyramid of Khafre Pyramid of Khufu Pyramid of Menkaure pyramid of number Pyramid of Sun Pyramid of the Moon

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。