Perhaps you should try some spelling variations:
tranh cua » doanh cua, manh cua
phan cong » thanh cong
hoi hieu » hoi phieu, hoi tieu, moi hieu
ban cong » bang cong, van cong, ban huong
bai toan » bai tap
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)) lang - canh tranh cua ((ban cong) OR (phan cong)) bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho hieu) OR (hoi hieu)) lang - canh tranh cua ((ban cong) OR (phan cong)) bai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho hieu) or (hoi hieu)) lang - canh tranh cua ((ban cong) OR (phan cong)) bai toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho hieu) or (hoi hieu)) lang - canh tranh cua ((ban cong) OR (phan cong)) bai toan cau*.