Perhaps you should try some spelling variations:
vien nganh » vien thanh
dong trong » duong trong, dung trong, cong trong
hieu xanh » chieu xanh, hieu manh, hieu nganh
hanh tang » hanh trang, anh tang, hanh mang
tang cua » mang cua, hang cua, tang luan
cua dong » chua dong, cua cong, cua dang
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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) or (vien nganh)) - hanh tang cua dong trong ((san toan) OR (dan toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (vien nganh)) - hanh tang cua dong trong ((san toan) OR (dan toan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) or (vien nganh)) - hanh tang cua dong trong ((san toan) OR (dan toan)) ban".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (vien nganh)) - hanh tang cua dong trong ((san toan) OR (dan toan)) ban*.