Perhaps you should try some spelling variations:
"resource research theories" » "resources research theories", "resource search theories", "source research theories", "resource research theory", "resource research themes", "resource research topics"
"rescue search theory" » "rescue sar theory", "rescue research theory"

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: (("resource research theories") OR ("rescue search theory")).
• Removing quotes may allow a broader search: (( resource research theories ) or ( rescue search theory )).
• Adding a wildcard symbol may retrieve word variants: (("resource research theories") or ("rescue search theory"))*.