Perhaps you should try some spelling variations:
"value n2o reactions" » "value two reactions", "value bio reactions", "value co reactions", "value 2 reactions", "value npv reactions", "value 12 reactions"
"value how ratio" » "value how ratios", "value how radio", "value low ratio"
"value co ratio" » "value co ratios", "value o ratio", "value h2o ratio"

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: (("value co ratio") OR ((("value n2o reactions") OR ("value how ratio")))).
• Removing quotes may allow a broader search: (( value co ratio ) or ((( value n2o reactions ) or ( value how ratio )))).
• Adding a wildcard symbol may retrieve word variants: (("value co ratio") or ((("value n2o reactions") or ("value how ratio"))))*.