Perhaps you should try some spelling variations:
"modified changing approximation algorithms" » "modified diophantine approximation algorithms", "modified caging approximation algorithms"
"modified objective allocation algorithm" » "modified objective estimation algorithm", "modified objective evolution algorithm", "modified objective predation 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 changing approximation algorithms") or ("modified objective allocation algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified changing approximation algorithms") OR ("modified objective allocation algorithm"))*.
• Removing quotes may allow a broader search: (( modified changing approximation algorithms ) or ( modified objective allocation algorithm ))*.