Perhaps you should try some spelling variations:
vien cac » vien bach, vien da, gian cac
vien dai » hien dai
san hanh » san thanh, van hanh, dan hanh
ban hanh » ban hang
ve triet » va trien, su triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
x hoi » xa hoi, o hoi, x ho
ve ve » de ve, va ve, ke ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang x hoi. hieu ((vien cac) OR (vien dai)) toc ((san hanh) or (ban hanh)) ve ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. hieu ((vien cac) OR (vien dai)) toc ((san hanh) OR (ban hanh)) ve ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x hoi. hieu ((vien cac) OR (vien dai)) toc ((san hanh) or (ban hanh)) ve ve triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((vien cac) OR (vien dai)) toc ((san hanh) or (ban hanh)) ve ve triet*.