Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trinh » canh tranh, hanh chinh
trong dong » trong cong, trong nong, trong dang
dong than » dong thanh, dong thuan, dong chan
trinh su » trinh tu, trinh san, trinh cau
than tap » toan tap, han tap, phan tap

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 sach) or (trieu tinh)) - hanh trinh su dung trong dong than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (trieu tinh)) - hanh trinh su dung trong dong than tap*.