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

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

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