Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
tranh han » tranh hang, trinh han, tranh ban
han nhung » hanh nhung, hon nhung, ban nhung
doi thoi » doi thoai, moi thoi, do thoi
cong bai » cuong bai, cong hai, cung bai
bai toan » bai tap
toan cao » toan ban, toan tap
doi thi » do thi, doi khi, doi thu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi thi) OR (doi thoi)) hanh - canh tranh han nhung cong bai toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi thi) OR (doi thoi)) hanh - canh tranh han nhung cong bai toan cao".
• Adding a wildcard symbol may retrieve word variants: ((doi thi) OR (doi thoi)) hanh - canh tranh han nhung cong bai toan cao*.