Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithms" » "modified multiobjective optimization algorithms", "modified multiobjective estimation algorithm", "modified multiobjective optimisation algorithm"
"modified passive evolutionary algorithm" » "modified passive evolution algorithm", "modified passive solution algorithm", "modified adaptive evolutionary algorithm"

Try widening your search to All Fields.

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

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