Perhaps you should try some spelling variations:
radiofrequency dischargess » radiofrequency discharges
radiofrequency images » radiofrequency mass, radiofrequency pulses, radiofrequency based
frequency discharges » frequency changes

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((((radiofrequency dischargess) OR (radiofrequency images))) OR (frequency discharges)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((radiofrequency dischargess) OR (radiofrequency images))) or (frequency discharges))".
• Adding a wildcard symbol may retrieve word variants: ((((radiofrequency dischargess) OR (radiofrequency images))) or (frequency discharges))*.