Perhaps you should try some spelling variations:
thanh dung » thanh duong, thanh tung, thanh hung
hieu sach » chieu sach, hieu cach, dien sach
cua thuoc » nha thuoc, cay thuoc, cua quoc
trong dan » trong dang, trong san, trong tan
doc hieu » toc thieu, hoc thieu, hoc hien
cua nuoc » cua quoc, cua nguoi, nha nuoc
toan cao » toan tap
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - thanh dung ((cua thuoc) OR (cua nuoc)) trong dan ((toan cao) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - thanh dung ((cua thuoc) OR (cua nuoc)) trong dan ((toan cao) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - thanh dung ((cua thuoc) OR (cua nuoc)) trong dan ((toan cao) or (toan ban))*.