Perhaps you should try some spelling variations:
"modified df convolution algorithms" » "modified df evolution algorithm", "modified df solution algorithm", "modified d convolutional algorithms", "modified _ convolution algorithms", "modified adam convolution algorithms", "modified bi1 convolution algorithms"
"modified objective estimation algorithms" » "modified objective estimation algorithm", "modified objective optimization algorithms", "modified objective optimisation algorithm", "modified objective allocation algorithms"

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 df convolution algorithms") or ("modified objective estimation algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified df convolution algorithms") OR ("modified objective estimation algorithms")).
• Removing quotes may allow a broader search: (( modified df convolution algorithms ) or ( modified objective estimation algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified df convolution algorithms") or ("modified objective estimation algorithms"))*.