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
thau dau » phan dau, chau au
dau sach » cau sach, dat sach, hau sach
vat dang » van dang, vat dung, va dang
dan toan » van toan, dan than, manh toan

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: thau dau sach - hanh trinh vat dang cong ((dan toan) OR (tan tran)) cau~.
• Adding a wildcard symbol may retrieve word variants: thau dau sach - hanh trinh vat dang cong ((dan toan) or (tan tran)) cau*.