Perhaps you should try some spelling variations:
vien nganh » vien thanh
hanh trang » thanh trung, canh tranh, minh trang
hanh trinh » canh tranh, hanh chinh
dong trong » duong trong, dung trong, cong trong
hieu xanh » chieu xanh, hieu manh, hieu nganh
trong dan » trong dang, trong san, trong tan
cua dong » chua dong, cua cong, cua dang
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) OR (hanh trinh)) cua dong 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) OR (hanh trinh)) cua dong 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) OR (hanh trinh)) cua dong trong dan van ban".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (vien nganh)) - ((hanh trang) OR (hanh trinh)) cua dong trong dan van ban*.