Perhaps you should try some spelling variations:
"modified objective optimization algorithm" » "modified multiobjective optimization algorithm", "modified objective optimization algorithms", "modified objective optimisation algorithm", "modified objective estimation algorithm"
"machines using search algorithm" » "machines using source algorithm", "machinery using search algorithm", "machines using egarch algorithm", "machines nursing research algorithm", "machines using servo algorithm"

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

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