Perhaps you should try some spelling variations:
fluid interfaces » liquid interfaces, solid interfaces, liquid interface
used interfaces » user interfaces, based interfaces, based interface
und interfaces » liquid interfaces, based interfaces, solid interfaces

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: ((used interfaces) OR (((und interfaces) OR (fluid interfaces)))) (computer systems).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((used interfaces) or (((und interfaces) OR (fluid interfaces)))) (computer systems)".
• Adding a wildcard symbol may retrieve word variants: ((used interfaces) or (((und interfaces) OR (fluid interfaces)))) (computer systems)*.