Perhaps you should try some spelling variations:
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"
"modified four solution algorithm" » "modified four evolution algorithm", "modified four convolution algorithms", "modified four evolutionary algorithm", "modified near solution algorithm", "modified flour solution algorithm", "modified drug 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 four solution algorithm\") OR (\"modified notion approximation algorithms\"))~".
• Removing quotes may allow a broader search: (( modified four solution algorithm ) OR ( modified notion approximation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified four solution algorithm") OR ("modified notion approximation algorithms"))*.