A human-computer interface for a search engine or similar application includes specification means for a time condition applicable to a search query, and visual feedback means expressive of relative availability of sought or potentially sought database items at one or more specific times within a time period under consideration. The invention provides a new and unique way to support interactive searching of a database that includes information relating to time availability of represented items, in order to identify items that match one or more search term(s) and are available at a specific time or during a specific time period.