Perhaps you should try some spelling variations:
"open resources software" » "open outsourced software", "open measures software", "ocean resources software", "open sources software", "own resources software", "open sourcess software", "min resources software"
"open resource software" » "open opensource software", "open resonance software", "open reduce software", "ocean resource software", "open sources software", "min resource software"

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: (("open source software") OR ((("open resource software") OR ("open resources software")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"open source software\") or (((\"open resource software\") OR (\"open resources software\"))))".
• Removing quotes may allow a broader search: (( open source software ) or ((( open resource software ) OR ( open resources software )))).
• Adding a wildcard symbol may retrieve word variants: (("open source software") or ((("open resource software") OR ("open resources software"))))*.