Perhaps you should try some spelling variations:
"modified df optimization algorithm" » "modified df optimization algorithms", "modified df optimisation algorithm", "modified df estimation algorithm", "modified _ optimization algorithm", "modified qoe optimization algorithm", "modified _ optimisation algorithm", "modified adam optimization algorithm", "modified bi1 optimization algorithm"
"machine learning method algorithm" » "machine learning mom algorithm", "machine learning methods algorithm", "machine graining methods algorithm", "machine learning emotion algorithm"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified df optimization algorithm") or ("machine learning method algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified df optimization algorithm") OR ("machine learning method algorithm")).
• Removing quotes may allow a broader search: (( modified df optimization algorithm ) or ( machine learning method algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified df optimization algorithm") or ("machine learning method algorithm"))*.