Perhaps you should try some spelling variations:
"resourcesssssssssssssssssssssssssssssss detection function" » "resourcessssssssssssssssssssssssssssssss detection function" (Expand Search)
"source selection functions" » "sources selection functions" (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: (("resourcesssssssssssssssssssssssssssssss detection function") OR ("source selection functions"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"resourcesssssssssssssssssssssssssssssss detection function\") OR (\"source selection functions\"))*".
• Removing quotes may allow a broader search: (( resourcesssssssssssssssssssssssssssssss detection function ) OR ( source selection functions ))*.