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

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("complementar constrained problema") OR ("complementarity constraints problemes"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"complementar constrained problema\") OR (\"complementarity constraints problemes\"))*".
• Removing quotes may allow a broader search: (( complementar constrained problema ) OR ( complementarity constraints problemes ))*.