Perhaps you should try some spelling variations:
"modified positive convolution algorithms" » "modified positive evolution algorithm", "modified positive solution algorithm", "modified positive solutions algorithms", "modified passive convolution algorithms", "modified adaptive convolution algorithms"
"modified parameters estimation algorithm" » "modified parameter estimation algorithm", "modified parameter estimates algorithm", "modified parameter optimization algorithm"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified positive convolution algorithms") or ("modified parameters estimation algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified positive convolution algorithms") OR ("modified parameters estimation algorithm")).
• Removing quotes may allow a broader search: (( modified positive convolution algorithms ) or ( modified parameters estimation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified positive convolution algorithms") or ("modified parameters estimation algorithm"))*.