Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
vuc nang » cuc nang, chuc nang, van nang
tai hoi » tai khoi, dai hoi, tai hai
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, xuc ban
vuc van » duc van, luc van, thuc van
vu nang » va nang, vu dang, v nang
hanh ki » hanh vi, hanh ky, hanh kien
tu sach » thu sach, su sach, te sach
va cam » va cham, va cac, va cao
ki su » ky su

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 ((vu nang) OR (vuc nang)) tai hoi. hieu va cam ((xuc van) or (vuc van)) hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((vu nang) OR (vuc nang)) tai hoi. hieu va cam ((xuc van) OR (vuc van)) hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((vu nang) OR (vuc nang)) tai hoi. hieu va cam ((xuc van) or (vuc van)) hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((vu nang) OR (vuc nang)) tai hoi. hieu va cam ((xuc van) or (vuc van)) hanh ki su triet*.