Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithm" » "modified multiobjective optimization algorithms", "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithms"
"defined network estimation algorithm" » "defined network optimization algorithm", "designed network estimation algorithm"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"defined network estimation algorithm\") OR (\"modified multiobjective optimization algorithm\"))~".
• Removing quotes may allow a broader search: (( defined network estimation algorithm ) OR ( modified multiobjective optimization algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("defined network estimation algorithm") OR ("modified multiobjective optimization algorithm"))*.