Perhaps you should try some spelling variations:
"modified location estimation algorithms" » "modified location estimation algorithm", "modified location optimization algorithms", "modified location optimisation algorithm", "modified motion estimation algorithms", "modified carbon estimation algorithms"
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified location estimation algorithms") OR ("modified notion approximation algorithms"))~.
• Removing quotes may allow a broader search: (( modified location estimation algorithms ) or ( modified notion approximation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified location estimation algorithms") or ("modified notion approximation algorithms"))*.