Perhaps you should try some spelling variations:
"modified objective approximation algorithm" » "modified objective approximation algorithms"
"modified policy optimization algorithm" » "modified policy optimization algorithms", "modified policy optimisation algorithm", "modified policy estimation algorithm", "modified topology optimization 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 policy optimization algorithm") OR ("modified objective approximation algorithm"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified policy optimization algorithm\") OR (\"modified objective approximation algorithm\"))".
• Removing quotes may allow a broader search: (( modified policy optimization algorithm ) OR ( modified objective approximation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified policy optimization algorithm") OR ("modified objective approximation algorithm"))*.