Perhaps you should try some spelling variations:
"resourcesssssssssssssssss selection functions" » "resourcesssssssssssssssss detection functions" (Expand Search), "resourcesssssssssssssssss selection function" (Expand Search), "resourcessssssssssssssssss selection functions" (Expand Search)
"source selection functions" » "source detection functions" (Expand Search), "source selection function" (Expand Search), "sources selection functions" (Expand Search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"resourcesssssssssssssssss selection functions\") OR (\"source selection functions\"))~".
• Removing quotes may allow a broader search: (( resourcesssssssssssssssss selection functions ) OR ( source selection functions ))~.
• Adding a wildcard symbol may retrieve word variants: (("resourcesssssssssssssssss selection functions") OR ("source selection functions"))*.