Perhaps you should try some spelling variations:
approximation algorithm » approximation algorithms
estimation algorithms » estimation algorithm, optimization algorithms, optimisation algorithm
static estimation » static optimization
df approximation » _ approximation, one approximation, time approximation
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 approximation algorithm ) OR ( modified static estimation algorithms ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified df approximation algorithm ) OR ( modified static estimation algorithms ))*.