Perhaps you should try some spelling variations:
regarding papers » regarding patents, regarding aps, regarding expert
regarding others » regarding other, regarding them, safeguarding others
food economics » cloud economics, land economics
oecd economies » oecd economic
food economy » old economy, world economy

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: ((((food economics) OR (food economy))) OR (oecd economies)) development ((regarding papers) OR (regarding others)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((food economics) OR (food economy))) or (oecd economies)) development ((regarding papers) or (regarding others))".
• Adding a wildcard symbol may retrieve word variants: ((((food economics) OR (food economy))) or (oecd economies)) development ((regarding papers) or (regarding others))*.