Perhaps you should try some spelling variations:
experimental reports » experimental report, experimental results, experimental remarks
world economics » world economic, world economy, food economics
oecd economies » oecd economic
reports papers » ports papers, report paper, reprints papers

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: ((world economics) OR (oecd economies)) experimental reports papers.
• Adding a wildcard symbol may retrieve word variants: ((world economics) or (oecd economies)) experimental reports papers*.