Perhaps you should try some spelling variations:
"social net model" » "social news model", "social na model", "social needs model"
"social dea model" » "social idea model", "social de model", "social del model", "social dea models"
"social da model" » "social de model", "social data model", "social del model", "social lda model", "social dna model", "social mda 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 net model") OR ((("social da model") OR ("social dea model"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social net model\") or (((\"social da model\") OR (\"social dea model\"))))*".
• Removing quotes may allow a broader search: (( social net model ) or ((( social da model ) OR ( social dea model ))))*.