Perhaps you should try some spelling variations:
"social effects model" » "special effects model", "social aspects model", "societal effects model", "focal effects model", "social effects models"
"social effect model" » "societal effect model", "special effect model", "focal effect model", "social effects models", "social effective model", "social object model"
"social exact model" » "social etats model", "social et model", "social email model"
"local effect models" » "local effects modelss", "local effective models", "local object models", "local effects models", "global effect models", "legal effect models"

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 exact model") OR ((((("social effect model") OR ("local effect models"))) OR ("social effects model")))).
• Removing quotes may allow a broader search: (( social exact model ) or ((((( social effect model ) or ( local effect models ))) or ( social effects model )))).
• Adding a wildcard symbol may retrieve word variants: (("social exact model") or ((((("social effect model") or ("local effect models"))) or ("social effects model"))))*.