Perhaps you should try some spelling variations:
"complementaridade constrained problema" » "complementaridade contained problema" (Expand Search), "complementaridade constrained problemas" (Expand Search)
"complementarity constraints problemassasa" » "complementarity constraints problemasssasa" (Expand Search), "complementar constraints problemassasa" (Expand Search)

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: (("complementaridade constrained problema") OR ("complementarity constraints problemassasa"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"complementaridade constrained problema\") OR (\"complementarity constraints problemassasa\"))".
• Removing quotes may allow a broader search: (( complementaridade constrained problema ) OR ( complementarity constraints problemassasa )).
• Adding a wildcard symbol may retrieve word variants: (("complementaridade constrained problema") OR ("complementarity constraints problemassasa"))*.