Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh vat » trinh van, trinh luat, sinh vat
dang cong » dung cong
vang toan » dang toan, quang toan, vang trang
dau sach » cau sach, dat sach, rau sach
hau sach » khau sach, cau sach, ham sach
vat dang » van dang, vat dung, va dang
van toan » van tuan, van tan, van thanh

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

• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((dau sach) OR (hau sach)) - hanh trinh vat dang cong ((vang toan) OR (van toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((dau sach) OR (hau sach)) - hanh trinh vat dang cong ((vang toan) or (van toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: theo ((dau sach) OR (hau sach)) - hanh trinh vat dang cong ((vang toan) or (van toan)) cau*.