Perhaps you should try some spelling variations:
"modified multiobjective approximation algorithms" » "modified multiobjective optimization algorithms"
"machines learning methods algorithm" » "machine learning methods algorithm", "active learning methods algorithm", "mapping learning methods algorithm", "machines nursing methods algorithm"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("machines learning methods algorithm") OR ("modified multiobjective approximation algorithms"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"machines learning methods algorithm\") OR (\"modified multiobjective approximation algorithms\"))*".
• Removing quotes may allow a broader search: (( machines learning methods algorithm ) OR ( modified multiobjective approximation algorithms ))*.