Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nha thuoc, cay thuoc
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
tai cua » thai cua, tai cuc, tri cua
dan tai » van tai, dan thi, han tai
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, lang van
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau

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 ((lang xa) OR (dang xay)) hoi. hieu va ((nam thu) or (nam thuoc)) va dan tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((lang xa) OR (dang xay)) hoi. hieu va ((nam thu) OR (nam thuoc)) va dan tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((lang xa) OR (dang xay)) hoi. hieu va ((nam thu) or (nam thuoc)) va dan tai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang xa) OR (dang xay)) hoi. hieu va ((nam thu) or (nam thuoc)) va dan tai cua tre*.