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

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

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