Perhaps you should try some spelling variations:
trung huong » truong huong, trung uong, trung duong
hanh tranh » canh tranh, hanh trinh, hanh trang
chieu sang » chieu sach, chieu xanh, hieu lang
hieu manh » chieu xanh, hieu nganh, dieu hanh
tranh cua » doanh cua, manh cua
cua trung » cua truong, xuan trung, cua nhung
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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 (hieu manh)) - hanh tranh cua trung huong ((dan toan) OR (van toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (hieu manh)) - hanh tranh cua trung huong ((dan toan) OR (van toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sang) or (hieu manh)) - hanh tranh cua trung huong ((dan toan) OR (van toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) or (hieu manh)) - hanh tranh cua trung huong ((dan toan) OR (van toan)) cao*.