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