Perhaps you should try some spelling variations:
"open resources" » "ocean resources", "own resources", "when resources", "min resources", "non resources"
"open resource" » "ocean resource", "min resource", "non resource"
"open sources" » "ion sources", "main sources"

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: (("open source") OR ((("open resource") OR ((("open resources") OR ("open sources"))))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"open source\") or (((\"open resource\") or (((\"open resources\") OR (\"open sources\"))))))*".
• Removing quotes may allow a broader search: (( open source ) or ((( open resource ) or ((( open resources ) OR ( open sources ))))))*.