Perhaps you should try some spelling variations:
"open resource software" » "open resources software" (Expand Search)
"open reresourcesss software" » "open reresourcessss software" (Expand Search), "open reresourcess software" (Expand Search)
"open resourcess software" » "open resourcesss software" (Expand Search), "open resources software" (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("open resource software") OR ("open reresourcesss software"))) OR ("open resourcess software"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"open resource software\") OR (\"open reresourcesss software\"))) OR (\"open resourcess software\"))".
• Removing quotes may allow a broader search: (((( open resource software ) OR ( open reresourcesss software ))) OR ( open resourcess software )).
• Adding a wildcard symbol may retrieve word variants: (((("open resource software") OR ("open reresourcesss software"))) OR ("open resourcess software"))*.