Perhaps you should try some spelling variations:
"modified df approximation algorithm" » "modified df approximation algorithms", "modified _ approximation algorithm", "modified one approximation algorithm", "modified time approximation algorithm", "modified adam approximation algorithm", "modified bi1 approximation algorithm"
"modified pose estimation algorithms" » "modified pose estimation algorithm", "modified pose optimization algorithms", "modified pose optimisation algorithm", "modified male estimation algorithms", "modified passive estimation 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 approximation algorithm") or ("modified pose estimation algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified df approximation algorithm") OR ("modified pose estimation algorithms")).
• Removing quotes may allow a broader search: (( modified df approximation algorithm ) or ( modified pose estimation algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified df approximation algorithm") or ("modified pose estimation algorithms"))*.