Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms"
"modified orthogonal deposition algorithm" » "modified orthogonal decomposition algorithm", "modified orthogonal evolution algorithm", "modified orthogonal solution algorithm"

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: "((\"modified orthogonal deposition algorithm\") OR (\"modified coverage approximation algorithms\"))~".
• Removing quotes may allow a broader search: (( modified orthogonal deposition algorithm ) OR ( modified coverage approximation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified orthogonal deposition algorithm") OR ("modified coverage approximation algorithms"))*.