Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
hanh dung » thanh dung, anh dung, hanh dong
dung song » dung dong, vung song, dong song
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
van tai » von tai, van tuan
tai tap » bai tap, tai tao, hai tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu xanh - hanh dung luan ((dung song) or (dung cong)) van tai tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh dung luan ((dung song) OR (dung cong)) van tai tap.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh dung luan ((dung song) or (dung cong)) van tai tap*.