Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
doc sach » hoc sach, toc sach, nuoc sach
vai cuu » vai cua
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky ((lang xa) or (nang x)) hoi. hieu va nam thuoc ((va dan) OR (ca dan)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky ((lang xa) OR (nang x)) hoi. hieu va nam thuoc ((va dan) OR (ca dan)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky ((lang xa) or (nang x)) hoi. hieu va nam thuoc ((va dan) OR (ca dan)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ky ((lang xa) or (nang x)) hoi. hieu va nam thuoc ((va dan) OR (ca dan)) vai cuu tre*.