Perhaps you should try some spelling variations:
"resourcessssssssssssssssssssssssss selection functions" » "resourcessssssssssssssssssssssssss detection functions" (Expand Search), "resourcessssssssssssssssssssssssss selection function" (Expand Search), "resourcesssssssssssssssssssssssssss 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: "((\"resourcessssssssssssssssssssssssss selection functions\") OR (\"source selection functions\"))~".
• Removing quotes may allow a broader search: (( resourcessssssssssssssssssssssssss selection functions ) OR ( source selection functions ))~.
• Adding a wildcard symbol may retrieve word variants: (("resourcessssssssssssssssssssssssss selection functions") OR ("source selection functions"))*.