Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithms" » "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithms", "modified multiobjective optimized algorithms"
"modified df estimation algorithm" » "modified _ estimation algorithm", "modified adam estimation algorithm", "modified bi1 estimation 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 df estimation algorithm") or ("modified multiobjective optimization algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified df estimation algorithm") OR ("modified multiobjective optimization algorithms"))*.
• Removing quotes may allow a broader search: (( modified df estimation algorithm ) or ( modified multiobjective optimization algorithms ))*.