Perhaps you should try some spelling variations:
"special respect de" » "special aspects de", "special report de", "special request de", "special respect _"
"special effect model" » "special effects model", "spectral effects model", "social effects model", "special effect models", "special effects models"
"social effect model" » "social effects model", "societal effect model", "local effect model", "social effect models", "social effects models"

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 effect model") OR ((("special effect model") OR ("special respect de"))))*.
• Removing quotes may allow a broader search: (( social effect model ) or ((( special effect model ) or ( special respect de ))))*.