Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu xanh » chieu xanh, hieu manh, hieu nganh
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
trung va » truong va, trang va, trung ha
van toan » van tuan, van tan, van thanh
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 - thanh ((trung va) or (dung va)) ((dung cong) or (thong cong)) van toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - thanh ((trung va) OR (dung va)) ((dung cong) OR (thong cong)) van toan cao.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - thanh ((trung va) or (dung va)) ((dung cong) or (thong cong)) van toan cao*.