Perhaps you should try some spelling variations:
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"
"machines learning method algorithm" » "machine learning method algorithm", "active learning method algorithm", "mapping learning method algorithm", "machines learning mom algorithm", "machines learning methods algorithm", "machines graining methods algorithm", "machines 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: (("modified notion approximation algorithms") OR ("machines learning method algorithm"))~.
• Removing quotes may allow a broader search: (( modified notion approximation algorithms ) or ( machines learning method algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified notion approximation algorithms") or ("machines learning method algorithm"))*.