Perhaps you should try some spelling variations:
knowledge economic » knowledge economies
knolwedge economy » knowledge economy's
knowledge ecology » knowledge technology, knowledge sociology, knowledge ecologies
knowlege economy » knowledge economy's, knowledge economies

Try widening your search to All Fields.

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: %((((((knowlege economy) OR (((knolwedge economy) OR (knowledge ecology))))) OR (knowledge economic))) OR (knowledge economy))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((((((knowlege economy) or (((knolwedge economy) OR (knowledge ecology))))) or (knowledge economic))) or (knowledge economy))%22".
• Adding a wildcard symbol may retrieve word variants: %((((((knowlege economy) or (((knolwedge economy) OR (knowledge ecology))))) or (knowledge economic))) or (knowledge economy))%22*.