Perhaps you should try some spelling variations:
"modified cover optimization algorithms" » "modified cover optimisation algorithm", "modified cover estimation algorithms", "modified cover estimation algorithm", "modified qoe optimization algorithms", "modified game optimization algorithms"
"modified objective allocation algorithm" » "modified objective estimation algorithm", "modified objective evolution algorithm", "modified objective predation algorithm"

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