Perhaps you should try some spelling variations:
thanh trung » thanh tung
phuong doan » phuong loan, phuong hoang, huong dan
phuong dan » phuong danh, huong dan, phuong lan
hieu sach » chieu sach, hieu cach, hieu cac
dien sach » dien anh
trung cua » truong cua, trung tuan, trung cap
cua dung » cua dang, cua dong, qua dung
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: doc ((hieu sach) OR (dien sach)) - thanh trung cua dung ((phuong dan) or (phuong doan)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sach) OR (dien sach)) - thanh trung cua dung ((phuong dan) OR (phuong doan)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sach) OR (dien sach)) - thanh trung cua dung ((phuong dan) or (phuong doan)) toan cao".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sach) OR (dien sach)) - thanh trung cua dung ((phuong dan) or (phuong doan)) toan cao*.