Perhaps you should try some spelling variations:
"complementaridade constrained problemasssasasasa" » "complementaridade contained problemasssasasasa" (Expand Search), "complementaridade constrained problemassssasasasa" (Expand Search)
"complementar constraints problema" » "complementar constraints problemas" (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 problemasssasasasa\") OR (\"complementar constraints problema\"))~".
• Removing quotes may allow a broader search: (( complementaridade constrained problemasssasasasa ) OR ( complementar constraints problema ))~.
• Adding a wildcard symbol may retrieve word variants: (("complementaridade constrained problemasssasasasa") OR ("complementar constraints problema"))*.