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

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: %((((((knowledge ecology) OR (knolwedge economy))) OR (knowledge economic))) OR (knowledge economy))%22.
• Adding a wildcard symbol may retrieve word variants: %((((((knowledge ecology) or (knolwedge economy))) or (knowledge economic))) or (knowledge economy))%22*.