Perhaps you should try some spelling variations:
chieu sach » chinh sach, chieu sang, chieu xanh
canh trinh » canh tranh, hanh trinh, canh tinh
duong tien » dong tien, phuong tien, luong tin
duong vien » duong van
trinh va » trinh van, trinh vat, trinh ve
toan cau » toan cao, toan ban, toan tap
va hung » va nhung, van hung, va huong

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)) - canh trinh va hung ((duong tien) or (duong vien)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chieu sach) OR (chiet tach)) - canh trinh va hung ((duong tien) OR (duong vien)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chieu sach) OR (chiet tach)) - canh trinh va hung ((duong tien) or (duong vien)) toan cau".
• Adding a wildcard symbol may retrieve word variants: theo ((chieu sach) OR (chiet tach)) - canh trinh va hung ((duong tien) or (duong vien)) toan cau*.