Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
doi chieu » doc hieu, doi chi, ho chieu
hanh sinh » hanh tinh, hanh dinh, hinh sinh
cong dan » cong san, huong dan, cong dong
cong tan » cong tac, cong san, cong thanh
phan cac » nhan cach, phan dau, phan lap
sinh va » sinh vat, tinh va, dinh van
va cong » tai cong, cua cong

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) or (theo chieu)) xanh - hanh sinh va cong ((cong dan) OR (cong tan)) phan cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (theo chieu)) xanh - hanh sinh va cong ((cong dan) OR (cong tan)) phan cac.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (theo chieu)) xanh - hanh sinh va cong ((cong dan) OR (cong tan)) phan cac".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (theo chieu)) xanh - hanh sinh va cong ((cong dan) OR (cong tan)) phan cac*.