Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
quang xa » quan xa, quang va, quang xuan
quang ma » xquang ma, quang va, quang manh
nam thuc » nam thuoc, am thuc, nam thu
vai cua » dai cua, hai cua, lai cua
dan vai » dan va, dan tai, dan vat
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
va nam » van nam, ha nam, va nay
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) OR (doc sach)) tay ((quang xa) or (quang ma)) hoi. hieu va nam thuc va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) tay ((quang xa) OR (quang ma)) hoi. hieu va nam thuc va dan vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) tay ((quang xa) or (quang ma)) hoi. hieu va nam thuc va dan vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) tay ((quang xa) or (quang ma)) hoi. hieu va nam thuc va dan vai cua tre*.