Perhaps you should try some spelling variations:
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"
"modified chemical solution algorithm" » "modified chemical evolution algorithm", "modified chemical convolution algorithms", "modified chemical evolutionary algorithm", "modified thermal solution algorithm", "modified chemical reduction algorithm", "modified chemical reaction algorithm"

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

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