Perhaps you should try some spelling variations:
"elements tree algorithms" » "elements three algorithms" (Expand Search), "elements art algorithms" (Expand Search), "elements two algorithms" (Expand Search), "elements ree algorithms" (Expand Search), "element ree algorithms" (Expand Search), "elements res algorithms" (Expand Search)
"level using algorithm" » "level using algorithms" (Expand Search), "level routing algorithm" (Expand Search), "level fusion algorithm" (Expand Search), "levels using algorithm" (Expand Search)
"implement based algorithm" » "implemented based algorithm" (Expand Search), "implementing based algorithm" (Expand Search)

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("implement based algorithm") OR ("elements tree algorithms"))) OR ("level using algorithm"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"implement based algorithm\") OR (\"elements tree algorithms\"))) OR (\"level using algorithm\"))".
• Removing quotes may allow a broader search: (((( implement based algorithm ) OR ( elements tree algorithms ))) OR ( level using algorithm )).
• Adding a wildcard symbol may retrieve word variants: (((("implement based algorithm") OR ("elements tree algorithms"))) OR ("level using algorithm"))*.