Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithm" » "modified multiobjective optimization algorithm"
"defined network optimization algorithms" » "defined network optimisation algorithm", "defined network estimation algorithms", "defined network 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 multiobjective estimation algorithm") OR ("defined network optimization algorithms"))~.
• Removing quotes may allow a broader search: (( modified multiobjective estimation algorithm ) or ( defined network optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified multiobjective estimation algorithm") or ("defined network optimization algorithms"))*.