Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nha thuoc, cay thuoc
doc sach » hoc sach, nuoc sach, dac sac
toc sach » hoc sach, thuoc sach, nuoc sach
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
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: ((doc sach) OR (toc sach)) ky lang xa hoi. hieu va ((nam thuoc) or (nam thu)) va dan va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (toc sach)) ky lang xa hoi. hieu va ((nam thuoc) OR (nam thu)) va dan va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (toc sach)) ky lang xa hoi. hieu va ((nam thuoc) or (nam thu)) va dan va cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (toc sach)) ky lang xa hoi. hieu va ((nam thuoc) or (nam thu)) va dan va cuu tre*.