Perhaps you should try some spelling variations:
"_ estimation algorithms" » "_ estimation algorithm", "_ optimization algorithms", "_ optimisation algorithm"
"write optimizer algorithms" » "write optimized algorithms", "write optimization algorithms"
"risk optimized algorithm" » "risk optimized algorithms", "write optimized algorithm"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("_ estimation algorithms") or ((("risk optimized algorithm") or ("write optimizer algorithms"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("_ estimation algorithms") OR ((("risk optimized algorithm") OR ("write optimizer algorithms")))).
• Removing quotes may allow a broader search: (( _ estimation algorithms ) or ((( risk optimized algorithm ) or ( write optimizer algorithms )))).
• Adding a wildcard symbol may retrieve word variants: (("_ estimation algorithms") or ((("risk optimized algorithm") or ("write optimizer algorithms"))))*.