Perhaps you should try some spelling variations:
tenti » texti, kenti, teni
tent » text, kent, ten
test » text, west
best » west
problem » problema
problemas » problemaas
problems » problemas, problema
problemsas » problemasas, problemaas, problema, problemes, problemens

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: "Hilbert's (tenti OR (tent OR (test OR best))) (((problem OR problemas) OR problems) OR problemsas)~".
• Adding a wildcard symbol may retrieve word variants: Hilbert's (tenti OR (tent OR (test OR best))) (((problem OR problemas) OR problems) OR problemsas)*.