Perhaps you should try some spelling variations:
"social net model" » "social news model", "social na model", "social needs model", "social net models", "social nset model", "social net modele", "social nfet model"
"social jet model" » "social je model", "social act model", "social jetlag model", "social set model", "social jset model", "social jet modele", "social jfet model"
"social et model" » "social en model", "social e model", "social etats model", "social set model", "social et modele", "social fet 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 et model") OR ((("social net model") OR ("social jet model")))).
• Removing quotes may allow a broader search: (( social et model ) or ((( social net model ) or ( social jet model )))).
• Adding a wildcard symbol may retrieve word variants: (("social et model") or ((("social net model") or ("social jet model"))))*.