Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
thien hach » thien thanh, hien hanh
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
trung cua » truong cua, trung tuan, trung cap
sat phan » sat nhan, vat phan, xuat phan

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