Perhaps you should try some spelling variations:
su triet » su tien, ve triet
van hanh » van thanh, ban hanh, van anh
tham duc » pham duc, tham du, than duc
tu sach » thu sach, te sach, tu cach
va tham » van tham, va cham, va thanh
hanh ki » hanh vi, hanh ky, hanh kien
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
vu nang » vuc nang, va nang, vu dang
su sach » so sach, vu sach
su viet » so viet
ma hoi » mai hoi, xa hoi, ma hoa

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) or (su sach)) vu nang ma hoi. hieu va tham duc van hanh ki ((su triet) OR (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) vu nang ma hoi. hieu va tham duc van hanh ki ((su triet) OR (su viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) vu nang ma hoi. hieu va tham duc van hanh ki ((su triet) OR (su viet))*".