Perhaps you should try some spelling variations:
"social exact model" » "social effect model", "social etats model", "social et model"
"social set model" » "social seat model", "social asset model", "social self model"
"social net model" » "social news model", "social na model", "social needs model"

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 set model") OR ("social net model"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social exact model\") or (((\"social set model\") OR (\"social net model\"))))*".
• Removing quotes may allow a broader search: (( social exact model ) or ((( social set model ) OR ( social net model ))))*.