Search History allows you to access a history of any previous searches performed. This will include both saved searches as well as those which have not been saved.
In the Search pane, click on the ‘Search History’ option:
A dialog box will open listing your previous searches:
To perform a previous search again, click on the ‘Perform This Search Again’ button on the right of the search you wish to execute. The dialog will then disappear and your previous search criteria will be executed and the results thereof displayed.