Even if you didn't save your results to a list, you can access all of your previous searches from your history from both the Finder and Raiser home page.
(you can also view your entire search history in the account info section)
Recent Searches Video Tutorial
Select the search you wish to revisit and click on 'Add all to list' next to the export button to save your list!
Once you save your desired set of results, you can then find your saved list(s) in the 'Lists' tab on the dark blue navigation bar at the top of the page.