This document discusses how to filter search results on a search engine. It explains that users can click on "Search tools" to filter results by time period such as day, hour, week, month or year. It also notes that this refers to when something was written, not necessarily what it is about. Additionally, the document states that users can look exclusively at news stories or filter news results using search tools, and set a custom time range. Finally, it mentions that when searching videos, users can filter by video length.