Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
thong cua » thong quan, huong cua
trong tac » trong cac, trong tan, trong tuc
tuong tac » cong tac, luong tai, tuong lai
doc hieu » toc thieu, hoc thieu, hoc hien
thong tu » phong tuc, thong tin, thong ke
toan cao » toan ban, toan 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 ((thong cua) or (thong tu)) song ((trong tac) or (tuong tac)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((thong cua) OR (thong tu)) song ((trong tac) OR (tuong tac)) toan cao.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((thong cua) or (thong tu)) song ((trong tac) or (tuong tac)) toan cao*.