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 algorithms" » "modified chemical solution algorithm", "modified chemical evolution algorithm", "modified chemical convolution algorithms", "modified thermal solution algorithms", "modified chemical reduction algorithms", "modified chemical reaction algorithms"

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