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 self modeling" » "social self modifying"
"social exact model" » "social etats model", "social et model", "social email 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 exact model") OR ("social effect model"))) OR ("social self modeling")).
• Removing quotes may allow a broader search: (((( social exact model ) or ( social effect model ))) or ( social self modeling )).
• Adding a wildcard symbol may retrieve word variants: (((("social exact model") or ("social effect model"))) or ("social self modeling"))*.