Just in case the default searches are not getting you, your desired leads, you can add in Advanced Filters.
You can search by the last day your lead was active, up until 30 days. You can also search by first name, last name, phone, email or a wild search. Click on Go to proceed with the search.
Just in case you need more options for a search you can click on the Additional Filters button. When you do this box will appear. Once you enter in the details click Go.