Perhaps you should try some spelling variations:
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
hanh trang » thanh trung, hanh trinh, minh trang
thong doan » thong dan, trong doanh, thong hoang
va thong » va thuong, va phuong, he thong
doan van » doan va, hoang van, luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sang) OR (chieu sach)) - ((hanh trang) or (canh tranh)) va thong thong doan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (chieu sach)) - ((hanh trang) OR (canh tranh)) va thong thong doan van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sang) OR (chieu sach)) - ((hanh trang) or (canh tranh)) va thong thong doan van ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) OR (chieu sach)) - ((hanh trang) or (canh tranh)) va thong thong doan van ban*.