Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
chieu sach » chinh sach, chiet tach, chieu sang
hanh tranh » hanh trinh, hanh trang, lanh tranh
nhung cong » dung cong, thong cong, nhung don
hang cong » dang cong, hang nong, bang cong
chat thi » chat thai, chat tai, chat khi

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

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