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