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