Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithms" » "modified multiobjective optimization algorithms", "modified multiobjective estimation algorithm", "modified multiobjective optimisation algorithm"
"modified invasive evolutionary algorithm" » "modified invasive evolution algorithm", "modified invasive solution algorithm", "modified passive 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 invasive evolutionary algorithm") or ("modified multiobjective estimation algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified invasive evolutionary algorithm") OR ("modified multiobjective estimation algorithms")).
• Removing quotes may allow a broader search: (( modified invasive evolutionary algorithm ) or ( modified multiobjective estimation algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified invasive evolutionary algorithm") or ("modified multiobjective estimation algorithms"))*.