“首日封”的概念、定义、翻译、参考文献-科学参考

单词	首日封
释义	首日封 Encyclopedia 工学集邮品释 first day cover首日封在新邮票发行首日，将该套邮票的全套或单枚贴在特制信封、普通信封或纪念信封的右上角，加盖当日邮政日戳或特制的首日纪念邮戳的信封。
随便看	root acid phosphatase root activity root and butt rot disease root and knot root and tuber crop nutrition root and vine of manyprickle acanthopanax root apical meristem root architecture root ball plant root box experiment root canal filling materials root canal therapy root cap root cation exchange capacity, RCEC root cause analysis root clay root-closure root-clustering root condition root confinement root crops sowing machine root crown root cutter root datum root decomposition

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。