Perhaps you should try some spelling variations:
approximation algorithm » approximation algorithms
association algorithm » classification algorithm, estimation algorithm, approximation algorithms
solution algorithm » evolution algorithm, convolution algorithms, evolutionary algorithm
one approximation » time approximation, _ approximation, rough approximations

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( response ((association algorithm) OR (solution algorithm)) ) or ( one approximation algorithm ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( response ((association algorithm) OR (solution algorithm)) ) OR ( one approximation algorithm )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( response ((association algorithm) OR (solution algorithm)) ) or ( one approximation algorithm ))".
• Adding a wildcard symbol may retrieve word variants: (( response ((association algorithm) OR (solution algorithm)) ) or ( one approximation algorithm ))*.