Perhaps you should try some spelling variations:
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"
"case learning emotion algorithm" » "case learning evolution algorithm", "case learning estimation algorithm", "case learning predation algorithm", "case learning method algorithm", "based learning emotion algorithm", "a learning emotion algorithm"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("case learning emotion algorithm") OR ("modified notion approximation algorithms"))~.
• Removing quotes may allow a broader search: (( case learning emotion algorithm ) or ( modified notion approximation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("case learning emotion algorithm") or ("modified notion approximation algorithms"))*.