Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
dong cua » dung cua, cong cua, huong cua
bai toan » bai tap
toan ban » van ban
ha dong » hoat dong, van dong

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc thieu xanh - ha dong cua ((nhung cong) or (dung cong)) bai toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc thieu xanh - ha dong cua ((nhung cong) OR (dung cong)) bai toan ban.
• Adding a wildcard symbol may retrieve word variants: toc thieu xanh - ha dong cua ((nhung cong) or (dung cong)) bai toan ban*.