Perhaps you should try some spelling variations:
thanh tung » thanh cong
thien hach » thien thanh, hien hanh
dung cong » dung trong
hieu van » hieu va, thien van, lieu va
tung cua » trung cua, tuong cua, dung cua
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 van)) - thanh tung cua ((dang cong) OR (dung cong)) tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (hieu van)) - thanh tung cua ((dang cong) OR (dung cong)) tac toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien hach) or (hieu van)) - thanh tung cua ((dang cong) OR (dung cong)) tac toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien hach) or (hieu van)) - thanh tung cua ((dang cong) OR (dung cong)) tac toan cau*.