Perhaps you should try some spelling variations:
electrical discharges » electrical discharge, electric discharge
electrical imaging » electrical aging, electrical charging, electrical heating
electrical charge » electric charge, electrical discharge, electric discharge

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: (( electrical imaging ) OR ( ((electrical charge) OR (electrical discharges)) )).
• Adding a wildcard symbol may retrieve word variants: (( electrical imaging ) or ( ((electrical charge) or (electrical discharges)) ))*.