Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
su sach » so sach
vu sach » vu bach, vu khach
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
ve giao » te giao, viet giao, van giao
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
kem dau » ke dau, dem dau

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) or (vu sach)) ty xang xa hoi. hieu ve giao duc ((va hanh) OR (va danh)) kem dau tieng~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ty xang xa hoi. hieu ve giao duc ((va hanh) OR (va danh)) kem dau tieng.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) ty xang xa hoi. hieu ve giao duc ((va hanh) OR (va danh)) kem dau tieng".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ty xang xa hoi. hieu ve giao duc ((va hanh) OR (va danh)) kem dau tieng*.