Perhaps you should try some spelling variations:
"modified objective optimization algorithms" » "modified objective optimisation algorithm", "modified objective estimation algorithms", "modified objective estimation algorithm", "modified multiobjective optimization algorithms"
"modified adaptive approximation algorithms" » "modified time approximation algorithms", "modified passive 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 adaptive approximation algorithms") or ("modified objective optimization algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified adaptive approximation algorithms") OR ("modified objective optimization algorithms"))*.
• Removing quotes may allow a broader search: (( modified adaptive approximation algorithms ) or ( modified objective optimization algorithms ))*.