Perhaps you should try some spelling variations:
22knowledge economy » knowlege economy, knowledge economy's
knolwedge economy » knowlege economy, knowledge economy's
knowledge ecology » knowledge technology, knowledge sociology, knowledge ecologies

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