Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
chinh ta » chinh tai, chinh va
cong van » cong vang, cong san, song van
van toan » van tuan, van tan, van thanh
toan cau » 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 ((chinh ta) or (chinh tri)) dung cong van toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((chinh ta) OR (chinh tri)) dung cong van toan cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((chinh ta) or (chinh tri)) dung cong van toan cau*.