Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
thong cong » tong cong, thong thong, phong chong
tranh cua » doanh cua, manh cua
hoi hieu » hoi phieu, hoi tieu, moi hieu
tap toan » tap doan, tap quan, bai toan
toan cau » toan cao, toan ban, toan tap
ho hieu » ho chieu, nho hieu, co hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho hieu) or (hoi hieu)) quang - hanh tranh cua ((thong cong) or (trong cong)) tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho hieu) OR (hoi hieu)) quang - hanh tranh cua ((thong cong) OR (trong cong)) tap toan cau.
• Adding a wildcard symbol may retrieve word variants: ((ho hieu) or (hoi hieu)) quang - hanh tranh cua ((thong cong) or (trong cong)) tap toan cau*.