Yahoo is to introduce video, audio and picture results as answers to text searches.
The company said the new features were aimed at better understanding the intention of users doing searches and to get them to the information within a single search.
Yahoo Search Assist suggests related concepts to instantly refine a search, drawing on information Yahoo has about what users across its sites are saying when they comment upon weblinks, photos and video.
Search Assist is designed to be especially helpful when a person is searching for information on an unfamiliar topic. The feature senses when a searcher needs help with a search and it appears as a drop-down menu under the main search results box.
Yahoo said it was trying to combat what it calls "web search fatigue". Research conducted for Yahoo found that roughly 15 per cent of online adults find what want on their first search while most need three to four searches.
Yahoo is seeking to stem the steady gains that Google, the dominant supplier of web search, has made in market share for most of the past two years.
Market research firm Comscore said Google's share grew to 56.5 per cent of the US web search market in August, up 1.3 per cent from July.