Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, nuoc sach, toc san
doc sach » hoc sach, nuoc sach, dac sac
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
han tai » hang tai, nhan tai, van tai
dan han » dan chan, dan than, dan hanh
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
buu tre » cuu tre
va nam » van nam, ha nam, va nay

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