Perhaps you should try some spelling variations:
thieu tach » chiet tach, chieu sach, hieu cach
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
quan cong » qua cong, luan cong, quan dong
cong tac » cong ty
tac tran » tan tran, tac trai, tac tren
tran cau » tran chau, toan cau, ran cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu tach) OR (thien hach)) - hanh trinh ((quan cong) or (qua song)) cong tac tran cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu tach) OR (thien hach)) - hanh trinh ((quan cong) OR (qua song)) cong tac tran cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu tach) OR (thien hach)) - hanh trinh ((quan cong) or (qua song)) cong tac tran cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu tach) OR (thien hach)) - hanh trinh ((quan cong) or (qua song)) cong tac tran cau*.