Perhaps you should try some spelling variations:
chiet tach » chieu sach
hoc chiet » hoc thiet, hoc nhiet, hoc hien
dung cong » dung trong
tang van » dang van, hoang van, trong van
trang va » tran van, hang va
cong van » cong vang, cong san, song van
van tuan » van quan, van ban, anh tuan
tuan cau » toan cau, quan cau, tuan cu

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: hoc chiet tach - hanh ((tang van) OR (trang va)) dung cong van tuan cau~.
• Adding a wildcard symbol may retrieve word variants: hoc chiet tach - hanh ((tang van) or (trang va)) dung cong van tuan cau*.