Perhaps you should try some spelling variations:
optimized algorithms » optimized algorithm, optimizer algorithms, optimization algorithms
network estimation » network optimization
modified network » certified network, defined network, modified near
df optimized » _ optimized, _ optimize
modified df » modified _, modified adam, modified bi1

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( modified df optimized algorithms ) or ( modified network estimation algorithm ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( modified df optimized algorithms ) OR ( modified network estimation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (( modified df optimized algorithms ) or ( modified network estimation algorithm ))*.