Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, cay thuoc
nha thuoc » nha nuoc, nhan thuc, nha hoc
toc sach » hoc sach, doc sach, thuoc sach
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
dau vai » dau va, dau hai, dau tai
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
va dau » va dao

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

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