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