Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » am thuc, nam thu, nam tu
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
hieu va » hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va dan » ca dan, va dao, va dau
dan va » doan va, dan ca, ban va
va cuu » va cau, va chu, va huu

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