Perhaps you should try some spelling variations:
"designed network optimization algorithm" » "designed network optimization algorithms", "designed network optimisation algorithm", "designed network estimation algorithms", "defined network optimization algorithm"
"modified invasive estimation algorithm" » "modified invasive ventilation algorithm", "modified passive estimation algorithm"

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: (("designed network optimization algorithm") OR ("modified invasive estimation algorithm"))~.
• Removing quotes may allow a broader search: (( designed network optimization algorithm ) or ( modified invasive estimation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("designed network optimization algorithm") or ("modified invasive estimation algorithm"))*.