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