Perhaps you should try some spelling variations:
"modified adaptive quantization algorithms" » "modified adaptive optimization algorithms", "modified adaptive ventilation algorithms"
"modified passive estimation algorithms" » "modified passive estimation algorithm", "modified passive optimization algorithms", "modified passive optimisation algorithm", "modified pose estimation algorithms"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified passive estimation algorithms") OR ("modified adaptive quantization algorithms"))~.
• Removing quotes may allow a broader search: (( modified passive estimation algorithms ) or ( modified adaptive quantization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified passive estimation algorithms") or ("modified adaptive quantization algorithms"))*.