Perhaps you should try some spelling variations:
"element sampling algorithm" » "element scheduling algorithm" (Expand Search), "elements sampling algorithm" (Expand Search)
"element tree algorithms" » "elements tree algorithms" (Expand Search), "element three algorithms" (Expand Search), "element free algorithms" (Expand Search)
"element study algorithm" » "elements study algorithm" (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: "((((\"element tree algorithms\") OR (\"element study algorithm\"))) OR (\"element sampling algorithm\"))~".
• Removing quotes may allow a broader search: (((( element tree algorithms ) OR ( element study algorithm ))) OR ( element sampling algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (((("element tree algorithms") OR ("element study algorithm"))) OR ("element sampling algorithm"))*.