Perhaps you should try some spelling variations:
chinh huong » chinh phuong, chinh truong, dinh huong
hieu quang » thieu quang, hieu quan, hieu qua
hanh trinh » canh tranh, hanh chinh
trinh luan » trinh luat, trinh quan, trinh han
luan chinh » luan chi, hoan chinh, luat hinh
hieu lang » chieu sang, nhieu tang, hieu van
dan toan » van toan, dan than, manh 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: hoc ((hieu lang) OR (hieu quang)) - hanh trinh luan chinh huong ((dan toan) OR (anh tuan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu lang) OR (hieu quang)) - hanh trinh luan chinh huong ((dan toan) or (anh tuan)) cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) OR (hieu quang)) - hanh trinh luan chinh huong ((dan toan) or (anh tuan)) cau*.