Perhaps you should try some spelling variations:
vien nganh » vien thanh
trinh khoa » trinh hoa, sinh khoa, trinh hoi
tang huong » tang cuong, tang duong, hang thuong
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh kho » trinh khoi, trang cho, tran khoa
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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)) - canh ((tranh kho) OR (trinh khoa)) tang huong dan than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (vien nganh)) - canh ((tranh kho) OR (trinh khoa)) tang huong dan than cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) or (vien nganh)) - canh ((tranh kho) OR (trinh khoa)) tang huong dan than cau".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (vien nganh)) - canh ((tranh kho) OR (trinh khoa)) tang huong dan than cau*.