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

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