If you are talking about radio button, if you script it, you can use a "*".
If you are manually peforming the find then you can either have another field where they can enter it without the radio button, or you can add a new request for each value for the radio button.
Using '*' will match anything. Are you trying to find records where the field is empty? If so, create a button with the 'Perform Find' command, specify the find to be [Field: =]
thanks the scripts did the trick!