Perhaps you should try some spelling variations:
"social effect model" » "social effects model", "societal effect model", "special effect model", "social effects models", "social effective model"
"social effect models" » "social effects models", "societal effect models", "special effect models", "social effects modelss", "social effective models"
"social et model" » "social en model", "social e model", "social etats model", "social net model", "social set model", "social jet 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 et model") OR ((("social effect model") OR ("social effect models")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social et model\") or (((\"social effect model\") OR (\"social effect models\"))))".
• Removing quotes may allow a broader search: (( social et model ) or ((( social effect model ) OR ( social effect models )))).
• Adding a wildcard symbol may retrieve word variants: (("social et model") or ((("social effect model") OR ("social effect models"))))*.