Perhaps you should try some spelling variations:
chiet tach » chieu sach
trung tuan » trung thanh, trung tam, tran tuan
nhung cong » dung cong, thong cong, hang cong
trung cua » truong cua, trung cap, dung cua
cong bai » cuong bai, cong hai, cung bai
bai toan » bai tap
toan cau » 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: ho ((chinh sach) or (chiet tach)) - thanh ((trung cua) OR (trung tuan)) nhung cong bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chinh sach) OR (chiet tach)) - thanh ((trung cua) OR (trung tuan)) nhung cong bai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chinh sach) or (chiet tach)) - thanh ((trung cua) OR (trung tuan)) nhung cong bai toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((chinh sach) or (chiet tach)) - thanh ((trung cua) OR (trung tuan)) nhung cong bai toan cau*.