Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu manh » chieu xanh, hieu nganh, dieu hanh
manh toan » thanh toan, anh tuan, tinh toan
doc hieu » toc thieu, hoc thieu, hoc hien
dan toan » van toan, dan than, xuan toan
ha tong » han tong, ha dong, ha long
ha tang » phap tang, cao tang, kho tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu manh - hanh tranh ((ha tong) OR (ha tang)) cong ((dan toan) or (manh toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu manh - hanh tranh ((ha tong) OR (ha tang)) cong ((dan toan) OR (manh toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu manh - hanh tranh ((ha tong) OR (ha tang)) cong ((dan toan) or (manh toan)) cao".
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - hanh tranh ((ha tong) OR (ha tang)) cong ((dan toan) or (manh toan)) cao*.