信息选粹服务（Selective Dissemination of Information，又译专题选粹服务，简称SDI）是图书馆一种针对读者个别兴趣，选择最新信息的新知报导服务。图书馆会以主动积极的方式，定期提供信息服务，节省用户检索数据的时间，加强馆藏资源的利用。

广义的SDI定义为采取人工或自动的方式，针对个别用户提供现况通知服务，积极选择相关研究兴趣的新信息，主动定期传递给读者，特色在于筛选以及发送最新的信息。

SDI在图书馆参考服务中，属于间接服务的一种。所谓间接服务，是帮助读者利用或取得所需信息的工作，如工具书编辑、馆藏合作、馆际互借、文献传递、专题选粹服务等。

Selective dissemination of information ("SDI") was originally a phrase related to library and information science. SDI refers to tools and resources used to keep a user informed of new resources on specified topics.

SDI services pre-date the world wide web, and the term itself is somewhat dated. Contemporary analogous systems for SDI services include alerts, current awareness tools or trackers. These systems provide automated searches that inform the user of the availability of new resources meeting the user's specified keywords and search parameters. Alerts can be received a number of ways, including email, RSS feeds, voice mail, Instant messaging, and text messaging.