Perhaps you should try some spelling variations:
"modified multiobjective approximation algorithms" » "modified multiobjective optimization algorithms"
"modified drug solution algorithm" » "modified drug evolution algorithm", "modified drug convolution algorithms", "modified drug evolutionary algorithm", "modified df solution algorithm", "modified orca solution 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 multiobjective approximation algorithms") OR ("modified drug solution algorithm"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified multiobjective approximation algorithms\") OR (\"modified drug solution algorithm\"))".
• Removing quotes may allow a broader search: (( modified multiobjective approximation algorithms ) OR ( modified drug solution algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified multiobjective approximation algorithms") OR ("modified drug solution algorithm"))*.