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