Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu sach » chieu sach, thien hach, hieu cach
chiet tach » chieu sach
cong thanh » dong thanh, cong trinh, truong thanh
trung cua » truong cua, trung tuan, trung cap
cua thong » cua thuong, cua khong, cua tong
cong tan » cong tac, cong san, cong ty
than cau » toan cau, phan cau, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) or (chiet tach)) - thanh trung cua thong ((cong tan) OR (cong thanh)) than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chiet tach)) - thanh trung cua thong ((cong tan) OR (cong thanh)) than cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) or (chiet tach)) - thanh trung cua thong ((cong tan) OR (cong thanh)) than cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) or (chiet tach)) - thanh trung cua thong ((cong tan) OR (cong thanh)) than cau*.