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