Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
khoai chau » khoa chau, khoa phau, hai chau
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
khoan cau » khoan cam, khoan dau, toan cau
ho chieu » theo chieu, hoc thieu, doi chieu

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: ho chieu xanh - thanh ((trung cua) OR (trung cap)) dung trong cac ((khoan cau) OR (khoai chau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chieu xanh - thanh ((trung cua) or (trung cap)) dung trong cac ((khoan cau) OR (khoai chau))~".
• Adding a wildcard symbol may retrieve word variants: ho chieu xanh - thanh ((trung cua) or (trung cap)) dung trong cac ((khoan cau) OR (khoai chau))*.