Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithm" » "modified multiobjective optimization algorithms", "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithm"
"modified df approximation algorithms" » "modified _ approximation algorithms", "modified one approximation algorithms", "modified time approximation algorithms", "modified adam approximation algorithms", "modified bi1 approximation algorithms"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified df approximation algorithms") OR ("modified multiobjective optimization algorithm"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified df approximation algorithms\") OR (\"modified multiobjective optimization algorithm\"))*".
• Removing quotes may allow a broader search: (( modified df approximation algorithms ) OR ( modified multiobjective optimization algorithm ))*.