Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithms" » "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithms", "modified multiobjective optimized algorithms"
"active learning estimation algorithm" » "active learning emotion algorithm", "active lighting estimation algorithm", "machine learning 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: "((\"active learning estimation algorithm\") OR (\"modified multiobjective optimization algorithms\"))~".
• Removing quotes may allow a broader search: (( active learning estimation algorithm ) OR ( modified multiobjective optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("active learning estimation algorithm") OR ("modified multiobjective optimization algorithms"))*.