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