Perhaps you should try some spelling variations:
"modified allocation optimization algorithms" » "modified allocation optimisation algorithm", "modified allocation estimation algorithms", "modified allocation estimation algorithm", "modified location optimization algorithms"
"modified cliffs predation algorithm" » "modified cliffs predators algorithm", "modified cliffs estimation algorithm", "modified cliff prediction algorithm"

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 cliffs predation algorithm") OR ("modified allocation optimization algorithms"))~.
• Removing quotes may allow a broader search: (( modified cliffs predation algorithm ) or ( modified allocation optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified cliffs predation algorithm") or ("modified allocation optimization algorithms"))*.