Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
doi chieu » doc hieu, doi chi, ho chieu
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cong tac » cong ty
toan cao » toan tap
toan ban » van ban
tinh va » tich va, trinh van, trinh vat
va cong » tai cong, cua cong

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: doi chieu xanh - hanh tinh va cong ((cong san) OR (cong tac)) ((toan cao) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chieu xanh - hanh tinh va cong ((cong san) OR (cong tac)) ((toan cao) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: doi chieu xanh - hanh tinh va cong ((cong san) OR (cong tac)) ((toan cao) or (toan ban))*.