Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu xanh » chieu xanh, hieu manh, hieu nganh
trinh qua » trinh quan, trinh cua, trinh quang
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
qua dung » quang dung, su dung, qua song
cong tan » cong tac, cong san, cong thanh
than cap » thanh lap, thanh cac, than cua
khan cap » khan ap, khoan cam, phan cac
phan cau » phan dau, phan cac, phan tu

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: doc hieu xanh - hanh trinh qua dung cong tan ((((than cap) OR (khan cap))) OR (phan cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh trinh qua dung cong tan ((((than cap) OR (khan cap))) or (phan cau))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh trinh qua dung cong tan ((((than cap) OR (khan cap))) or (phan cau))*.