Perhaps you should try some spelling variations:
"modified orcad optimization algorithms" » "modified orcad optimisation algorithm", "modified orcad estimation algorithms", "modified orcad estimation algorithm", "modified orca optimization algorithms"
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"

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 ("modified orcad optimization algorithms"))~.
• Removing quotes may allow a broader search: (( modified notion approximation algorithms ) or ( modified orcad optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified notion approximation algorithms") or ("modified orcad optimization algorithms"))*.