Perhaps you should try some spelling variations:
"social effect model" » "social effects model", "societal effect model", "special effect model", "social effect models", "social effects 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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social et model\") OR (\"social effect model\"))".
• Removing quotes may allow a broader search: (( social et model ) OR ( social effect model )).
• Adding a wildcard symbol may retrieve word variants: (("social et model") OR ("social effect model"))*.