Perhaps you should try some spelling variations:
tay long » ta long, tay cong, tay dong
tac long » tac dong, ta long, tac trong
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
che hoc » cho hoc, che ho, che thuoc
hanh di » hanh vi, hanh de, hang di
hoa hoi » khoa hoi, hoa doi, hoc hoi
hieu ke » hieu kem, chieu ke, hieu ky
hoc van » hoc dan, hoc va, hoc vat
di cua » dai cua, doi cua, de cua
cua te » cua tu
ke che » ke he

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tay long) OR (tac long)) ((hoa hoi) OR (hoa hoc)). hieu ke che hoc van hanh di cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((tay long) OR (tac long)) ((hoa hoi) or (hoa hoc)). hieu ke che hoc van hanh di cua te~".
• Adding a wildcard symbol may retrieve word variants: te sach ((tay long) OR (tac long)) ((hoa hoi) or (hoa hoc)). hieu ke che hoc van hanh di cua te*.