扩展查找(Query expansion)，也有人从英文翻译为查找扩展、查找扩张、查找问句扩展、字词扩张、查找延伸、查找字词扩展、自动查找扩展、查找语扩充……等。为了改善信息检索召回率(Recall)，而将原来查找句增加新的关键字来重新查找，此一技术称为扩展查找。搜索引擎会将用户输入的查找句先做一次检索，根据检索出来的文档，选取出适合的关键字，加到查找句重新检索，借此来找出更多的相关文档。

扩展查找使用在以下技术中：

扩展查找是计算机科学的技术，尤其使用在信息检索和自然语言处理领域中

Query expansion (QE) is the process of reformulating a seed query to improve retrieval performance in information retrieval operations. In the context of search engines, query expansion involves evaluating a user's input (what words were typed into the search query area, and sometimes other types of data) and expanding the search query to match additional documents. Query expansion involves techniques such as: