Perhaps you should try some spelling variations:
22knowledge economy » knowlege economy, knowledge economic, knowledge economy's
knolwedge economy » knowlege economy, knowledge economy's, knowledge economic
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 economies))) OR (knowledge economy))%22.
• Adding a wildcard symbol may retrieve word variants: %((((((22knowledge economy) or (((knolwedge economy) or (knowledge ecology))))) or (knowledge economies))) or (knowledge economy))%22*.