Perhaps you should try some spelling variations:
"social etats model" » "social ethics model", "social rats model", "social beats model", "social hats model"
"social etas model" » "social eclas model", "social et model", "social era model", "social keras model", "social gas model", "social das model"
"social act model" » "social acts model", "social acl model", "social actor model", "social fact model", "social cct model", "social ct 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 etats model") OR ("social etas model"))) OR ("social act model")).
• Removing quotes may allow a broader search: (((( social etats model ) or ( social etas model ))) or ( social act model )).
• Adding a wildcard symbol may retrieve word variants: (((("social etats model") or ("social etas model"))) or ("social act model"))*.