Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu xanh
chieu sang » chieu xanh, hieu lang, nhieu tang
trung tuan » trung thanh, tran tuan, truong thanh
dung cong » dung trong
cong tan » cong tac, cong san, cong thanh
tan hang » tan khang, ban hang, van hang
hang dau » hang va, hang tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (chieu sang)) - hanh ((trung tuan) OR (trung tam)) dung cong tan hang dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chieu sang)) - hanh ((trung tuan) OR (trung tam)) dung cong tan hang dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chieu sang)) - hanh ((trung tuan) OR (trung tam)) dung cong tan hang dau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chieu sang)) - hanh ((trung tuan) OR (trung tam)) dung cong tan hang dau*.