Perhaps you should try some spelling variations:
"computer class associations" » "computer classes association", "computer les associations", "computer calms associations", "computer its associations", "computer classes associations", "computer chess associations", "computer clubs associations"
"computers class association" » "computers its association", "computers classes association", "computers chess association", "computers case association"
"computer glass association" » "computer grass association", "computer gas association", "computer gwas association", "computer flash association", "computer classes association"

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: (("computers class association") OR ((("computer glass association") OR ("computer class associations")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"computers class association\") or (((\"computer glass association\") OR (\"computer class associations\"))))".
• Removing quotes may allow a broader search: (( computers class association ) or ((( computer glass association ) OR ( computer class associations )))).
• Adding a wildcard symbol may retrieve word variants: (("computers class association") or ((("computer glass association") OR ("computer class associations"))))*.