The purchase of a keyword by an organization from search engine providers and social media companies so that when a keyword is used in a search, an advert for that organization is displayed on the Web pages that are returned by the search engine.
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。