Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithm" » "modified multiobjective optimization algorithms", "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithm"
"modified cover optimized algorithms" » "modified cover optimized algorithm", "modified cover optimizer algorithms", "modified cover optimization algorithms", "modified covers optimized algorithms", "modified over optimized algorithms"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified cover optimized algorithms") OR ("modified multiobjective optimization algorithm"))~.
• Removing quotes may allow a broader search: (( modified cover optimized algorithms ) or ( modified multiobjective optimization algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified cover optimized algorithms") or ("modified multiobjective optimization algorithm"))*.