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