Perhaps you should try some spelling variations:
teni » tenia, tenis, tenir
tenti » texti, kenti, teni
tent » text, kent, ten
test » text, west
best » west
problem » problema, problemas
problems » problemas, problemass, problema
problemes » problemaes, problemases, problemas, probleme, problema

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