Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms"
"modified positive evolution algorithm" » "modified positive solution algorithm", "modified positive evolutionary algorithm", "modified positive convolution algorithms", "modified positive solutions algorithm", "modified passive evolution algorithm", "modified adaptive evolution 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 positive evolution algorithm\") OR (\"modified coverage approximation algorithms\"))~".
• Removing quotes may allow a broader search: (( modified positive evolution algorithm ) OR ( modified coverage approximation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified positive evolution algorithm") OR ("modified coverage approximation algorithms"))*.