Perhaps you should try some spelling variations:
chieu sach » chinh sach, chieu sang, chieu xanh
hanh tranh » canh tranh, hanh trinh, hanh trang
chua dong » cua dong, ha dong, hoa dong
trong bai » trong ban, thong bai, trong hai
huy dong » ha dong
bai toan » bai tap
toan cau » toan cao, toan ban, toan tap

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) or (chiet tach)) - hanh tranh ((chua dong) OR (huy dong)) trong bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chieu sach) OR (chiet tach)) - hanh tranh ((chua dong) OR (huy dong)) trong bai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chieu sach) or (chiet tach)) - hanh tranh ((chua dong) OR (huy dong)) trong bai toan cau".
• Adding a wildcard symbol may retrieve word variants: theo ((chieu sach) or (chiet tach)) - hanh tranh ((chua dong) OR (huy dong)) trong bai toan cau*.