Perhaps you should try some spelling variations:
"social exact model" » "social effect model", "social et model", "social email model"
"social ethics model" » "social ethics models", "social ethics modern", "social ethical model"
"social etats model" » "social etas model", "social rats model", "social beats model"

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: (("social exact model") OR ((("social etats model") OR ("social ethics model")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social exact model\") or (((\"social etats model\") OR (\"social ethics model\"))))".
• Removing quotes may allow a broader search: (( social exact model ) or ((( social etats model ) OR ( social ethics model )))).
• Adding a wildcard symbol may retrieve word variants: (("social exact model") or ((("social etats model") OR ("social ethics model"))))*.