Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
hanh tran » hanh trang, thanh tran, hanh tram
tong cong » trong cong, cong cong, dung cong
vang toan » van toan, dang toan, quang toan
tran van » luan van
van tong » van thong, van trong, van tuong
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - hanh tran van tong cong ((vang toan) or (((dan toan) or (dan than)))) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh tran van tong cong ((vang toan) OR (((dan toan) OR (dan than)))) cao.
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh tran van tong cong ((vang toan) or (((dan toan) or (dan than)))) cao*.