Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hanh thang » nhanh thang, thanh thang, hanh trang
nhung cong » dung cong, thong cong, hang cong
ho chieu » hoc thieu, doi chieu, mot chieu
thang va » hang va, trang va, thong va
tan toan » tap toan, van toan, dan toan

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)) xanh - hanh thang va nhung cong ((tan toan) OR (tan tran)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo chieu) or (ho chieu)) xanh - hanh thang va nhung cong ((tan toan) OR (tan tran)) cao~".
• Adding a wildcard symbol may retrieve word variants: ((theo chieu) or (ho chieu)) xanh - hanh thang va nhung cong ((tan toan) OR (tan tran)) cao*.