Perhaps you should try some spelling variations:
thanh tung » thanh cong
thien hach » thien thanh, hien hanh
cong cong » cong dong, trong cong, dung cong
hieu cac » hieu luc, hieu va, hieu van
tung cua » trung cua, tuong cua, dung cua
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

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 (hieu cac)) - thanh tung cua cong cong tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (hieu cac)) - thanh tung cua cong cong tac toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thien hach) or (hieu cac)) - thanh tung cua cong cong tac toan cau*.