Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh, le thanh
vu sach » vu bach, su sach, vu khach
sach le » cach le, sach de, sach lo
xang xa » lang xa, mang xa, dang xay
hieu va » lieu va, hieu qua
va giao » van giao, va giai, va gia
ang xa » lang xa, mang xa, dang xay
san va » san van, ban va, dan 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) or (ang xa)) hoi. hieu va giao duc ((va thanh) OR (ban thanh)) san va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach le ((xang xa) OR (ang xa)) hoi. hieu va giao duc ((va thanh) OR (ban thanh)) san va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach le ((xang xa) or (ang xa)) hoi. hieu va giao duc ((va thanh) OR (ban thanh)) san va thiet".
• Adding a wildcard symbol may retrieve word variants: vu sach le ((xang xa) or (ang xa)) hoi. hieu va giao duc ((va thanh) OR (ban thanh)) san va thiet*.