Perhaps you should try some spelling variations:
"complementaridade obtained problema" » "complementaridade obtained problemas" (Expand Search)
"complementarity constraints problemasssasasasa" » "complementarity constraints problemassssasasasa" (Expand Search), "complementar constraints problemasssasasasa" (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: (("complementaridade obtained problema") OR ("complementarity constraints problemasssasasasa"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"complementaridade obtained problema\") OR (\"complementarity constraints problemasssasasasa\"))".
• Removing quotes may allow a broader search: (( complementaridade obtained problema ) OR ( complementarity constraints problemasssasasasa )).
• Adding a wildcard symbol may retrieve word variants: (("complementaridade obtained problema") OR ("complementarity constraints problemasssasasasa"))*.