To use the simple search function, type the subject name into the first search window and click 'Submit'.
Click on the drop-down menu to use the advanced search options.
Click the "NOT" box to restrict your search results to those that match the subject name you entered in the first search window, but excluding the subject entered in the second window.
Click "OR" on the drop-down menu to broaden your search results to those containing the subject name you entered in the first and the second search windows.