Perhaps you should try some spelling variations:
"oecd healthy working paper" » "oecd healthy work paper", "oecd healthy coping paper", "oecd healthy worker paper", "oecd wealth working paper", "der healthy working paper", "very healthy working paper", "oecd healthy working papers"
"old healthy working paper" » "old healthy work paper", "old healthy coping paper", "old healthy worker paper", "old healthy working papers", "sold healthy working paper"
"oecd health working paper" » "oecd health warning paper", "oecd health networking paper", "oecd health workers paper", "oecd health working papers"

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: (("oecd health working paper") OR ((("oecd healthy working paper") OR ("old healthy working paper")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"oecd health working paper\") or (((\"oecd healthy working paper\") OR (\"old healthy working paper\"))))".
• Removing quotes may allow a broader search: (( oecd health working paper ) or ((( oecd healthy working paper ) OR ( old healthy working paper )))).
• Adding a wildcard symbol may retrieve word variants: (("oecd health working paper") or ((("oecd healthy working paper") OR ("old healthy working paper"))))*.