The domain which lies at the top of a hierarchical naming scheme. For example, in the Internet Domain Name Service there are a number of top-level domains such as edu, gov, and net.
科学参考收录了60776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。