Perhaps you should try some spelling variations:
"policy estimation algorithms" » "policy optimization algorithms", "policy optimisation algorithm", "policy approximation algorithms", "pose estimation algorithms", "motion estimation algorithms"
"a simulation algorithms" » "a optimization algorithms", "a solution algorithm", "_ simulation algorithms"
"a estimation algorithm" » "_ estimation algorithm", "a destination algorithm", "_ estimating algorithm"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("policy estimation algorithms") or ((("a simulation algorithms") OR ("a estimation algorithm"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("policy estimation algorithms") OR ((("a simulation algorithms") OR ("a estimation algorithm")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"policy estimation algorithms\") or (((\"a simulation algorithms\") OR (\"a estimation algorithm\"))))".
• Removing quotes may allow a broader search: (( policy estimation algorithms ) or ((( a simulation algorithms ) OR ( a estimation algorithm )))).
• Adding a wildcard symbol may retrieve word variants: (("policy estimation algorithms") or ((("a simulation algorithms") OR ("a estimation algorithm"))))*.