Perhaps you should try some spelling variations:
"societal effect model" » "societal effects model", "social effects model", "society effects model", "societal effect models", "societal effects models", "societal effective model"
"special effects model" » "special effects models", "special effect models"
"social et model" » "social en model", "social e model", "social etats model", "social net model", "social set model", "social jet 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 et model") OR ("societal effect model"))) OR ("special effects model")).
• Removing quotes may allow a broader search: (((( social et model ) or ( societal effect model ))) or ( special effects model )).
• Adding a wildcard symbol may retrieve word variants: (((("social et model") or ("societal effect model"))) or ("special effects model"))*.