Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
truong cua » truong ca, truong quan, truong cao
hoc thiet » hoc thieu, hoc thuyet, hoc hien
dong cong » duong cong, dung cong, dang cong
tran chau » tranh chap, tran huu
cong tac » cong ty
tra cau » tra sau, ta cau, tra cuu

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 thiet tach - thanh ((dung cho) OR (truong cua)) dong cong tac ((tra cau) OR (tran chau))~.
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - thanh ((dung cho) or (truong cua)) dong cong tac ((tra cau) or (tran chau))*.