Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
ty tang » tay tang, ty xang, ty hang
xuc van » duc van, luc van, vuc van
sach ty » sach y, sach tu, sach thu
ve cac » va cac
ma hoi » mai hoi, xa hoi, me hoi
cua su » qua su

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 tang ((ma hoi) or (ma hoa)). hieu ((ve cac) OR (vien cac)) xuc van hanh dai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty tang ((ma hoi) OR (ma hoa)). hieu ((ve cac) OR (vien cac)) xuc van hanh dai cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty tang ((ma hoi) or (ma hoa)). hieu ((ve cac) OR (vien cac)) xuc van hanh dai cua su".
• Adding a wildcard symbol may retrieve word variants: te sach ty tang ((ma hoi) or (ma hoa)). hieu ((ve cac) OR (vien cac)) xuc van hanh dai cua su*.