Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va, hieu qua
va hanh » va thanh, va danh, ban hanh
cam tu » cam thu, nam tu, tam tu
dam tu » nam tu, tam tu, dam thuc

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty xang xa hoi. hieu va ((cam tu) OR (dam tu)) ((va hanh) or (van hanh)) bi dau tieng~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty xang xa hoi. hieu va ((cam tu) OR (dam tu)) ((va hanh) OR (van hanh)) bi dau tieng.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty xang xa hoi. hieu va ((cam tu) OR (dam tu)) ((va hanh) or (van hanh)) bi dau tieng".
• Adding a wildcard symbol may retrieve word variants: te sach ty xang xa hoi. hieu va ((cam tu) OR (dam tu)) ((va hanh) or (van hanh)) bi dau tieng*.