Perhaps you should try some spelling variations:
"value co ratio" » "value co ratios", "value h2o ratio", "value c5 ratio", "value c2 ratio"
"value o ratio" » "value 4 ratio", "value 3 ratio", "value 2 ratio", "value o ratios", "value 5 ratio"
"value a ratio" » "value a radio", "value a rating"

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: (("value co ratio") OR ((("value o ratio") OR ("value a ratio"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"value co ratio\") or (((\"value o ratio\") OR (\"value a ratio\"))))*".
• Removing quotes may allow a broader search: (( value co ratio ) or ((( value o ratio ) OR ( value a ratio ))))*.