Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithms" » "modified multiobjective optimization algorithms", "modified multiobjective estimation algorithm", "modified multiobjective optimisation algorithm"
"modified one approximation algorithm" » "modified one approximation algorithms", "modified time approximation algorithm", "modified _ approximation algorithm", "modified rough approximations algorithm", "modified male approximation algorithm", "modified near approximation algorithm", "modified orca approximation algorithm"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified one approximation algorithm") or ("modified multiobjective estimation algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified one approximation algorithm") OR ("modified multiobjective estimation algorithms")).
• Removing quotes may allow a broader search: (( modified one approximation algorithm ) or ( modified multiobjective estimation algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified one approximation algorithm") or ("modified multiobjective estimation algorithms"))*.