Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cac tuc » cac toc, cac tu, cac tac
tu sach » thu sach, su sach, te sach
hieu ve » hieu va
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky dang, ky tang, duy sang
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky sang) or (ky nang)) mai hoi. ((hieu ve) OR (hieu van)) cac tuc va hanh vai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky nang)) mai hoi. ((hieu ve) OR (hieu van)) cac tuc va hanh vai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) or (ky nang)) mai hoi. ((hieu ve) OR (hieu van)) cac tuc va hanh vai cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) or (ky nang)) mai hoi. ((hieu ve) OR (hieu van)) cac tuc va hanh vai cua triet*.