Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
chiet tach » chieu sach
hieu lang » chieu sang, hieu quang, nhieu tang
hanh hang » thanh hang, hang hang, hanh han
dong cong » duong cong, dung cong, dang cong
hang tai » hang va, dung tai
tai dong » thai dong, tai cong, tai tong
cong san » cong tac
san phan » san pham, van phan, sat phan
phan cau » phan dau, phan cac, phan tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thien hach) or (((chiet tach) or (hieu lang)))) - hanh hang tai dong cong san phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (((chiet tach) OR (hieu lang)))) - hanh hang tai dong cong san phan cau*.