Perhaps you should try some spelling variations:
"modified response approximation algorithms" » "modified one approximation algorithms", "modified response association algorithms"
"modified passive quantization algorithm" » "modified passive estimation algorithm", "modified adaptive quantization algorithm"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified response approximation algorithms") OR ("modified passive quantization algorithm"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified response approximation algorithms\") OR (\"modified passive quantization algorithm\"))".
• Removing quotes may allow a broader search: (( modified response approximation algorithms ) OR ( modified passive quantization algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified response approximation algorithms") OR ("modified passive quantization algorithm"))*.