Perhaps you should try some spelling variations:
vien nganh » vien thanh
hanh trang » thanh trung, canh tranh, hanh trinh
hieu xanh » chieu xanh, hieu manh, hieu nganh
cua duong » cua dong, cua huong, tuan duong
qua duong » quan duong, qua dung, qua dong
trong dan » trong dang, trong san, trong tan
dan van » dang van, doan van, dao van

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