Perhaps you should try some spelling variations:
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
hanh trung » thanh trung, hanh trang, manh trung
trung cua » truong cua, trung tuan, trung cap
cua thong » cua thuong, cua khong, cua tong
cong tac » cong ty
toan cao » toan ban, toan tap

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 sang) OR (chieu sach)) - hanh trung cua thong ((cong san) or (cong tac)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (chieu sach)) - hanh trung cua thong ((cong san) OR (cong tac)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sang) OR (chieu sach)) - hanh trung cua thong ((cong san) or (cong tac)) toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) OR (chieu sach)) - hanh trung cua thong ((cong san) or (cong tac)) toan cao*.