The feature announced Wednesday marks Google's latest attempt to deliver data that people are seeking more quickly as it tries to maintain the dominance of its lucrative Internet search engine.
Google Inc. is initially testing the feature with 1 million Gmail users who must sign up to participate.
Gmail's more than 425 million users already can search within their email accounts to find something they need, such as an order from Amazon.com or an airline reservation.
Now, Gmail users who join the trial will be shown a list of relevant emails on Google's main search results page if the correspondence contains a word entered in a search request.
Gmail search trial sign-up: http://g.co/searchtrial