Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
sach le » cach le, sach de, sach lo
le xang » le tang, le dang, le quang
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
dai va » mai va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach le xang xa hoi. ((hieu va) or (hieu qua)) giao duc ((va hanh) OR (va danh)) dai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach le xang xa hoi. ((hieu va) OR (hieu qua)) giao duc ((va hanh) OR (va danh)) dai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach le xang xa hoi. ((hieu va) or (hieu qua)) giao duc ((va hanh) OR (va danh)) dai va thiet".
• Adding a wildcard symbol may retrieve word variants: vu sach le xang xa hoi. ((hieu va) or (hieu qua)) giao duc ((va hanh) OR (va danh)) dai va thiet*.