Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hanh dung » thanh dung, anh dung, hanh dong
bang cong » dang cong, bang song, dung cong
hang cong » dang cong, hang nong, thanh cong
ho chieu » hoc thieu, doi chieu, mot chieu
tan toan » tan tran, tap toan, van toan
toan cau » toan cao, toan ban, toan tap

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: ((theo chieu) OR (ho chieu)) tinh - hanh dung luan ((bang cong) OR (hang cong)) tan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo chieu) or (ho chieu)) tinh - hanh dung luan ((bang cong) OR (hang cong)) tan toan cau~".
• Adding a wildcard symbol may retrieve word variants: ((theo chieu) or (ho chieu)) tinh - hanh dung luan ((bang cong) OR (hang cong)) tan toan cau*.