Perhaps you should try some spelling variations:
optimization algorithmssss » optimization algorithms, optimisation algorithm
objective optimization » multiobjective optimization
estimation algorithms » estimation algorithm, optimization algorithms, optimisation algorithm
df estimation » _ estimation
modified df » modified _, modified adam, modified bi1

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( modified df estimation algorithms ) OR ( modified objective optimization algorithmssss ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified df estimation algorithms ) OR ( modified objective optimization algorithmssss ))*.