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