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