Perhaps you should try some spelling variations:
"special respect model" » "special aspects model", "special report model", "special effect model", "special aspect model", "special respective model", "special respect de"
"social effect models" » "social effects models", "societal effect models", "special effect models"
"social exact model" » "social etats model", "social et model", "social email model"

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