Perhaps you should try some spelling variations:
"social exact model" » "social effect model", "social et model", "social email model"
"social etats model" » "social ethics model", "social etas model", "social rats model", "social beats model"
"social nets model" » "social news model", "social net model", "social needs 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 nets model")))).
• Removing quotes may allow a broader search: (( social exact model ) or ((( social etats model ) or ( social nets model )))).
• Adding a wildcard symbol may retrieve word variants: (("social exact model") or ((("social etats model") or ("social nets model"))))*.