Perhaps you should try some spelling variations:
nguoi sach » nguoi san, nuoc sach
toc sach » hoc sach, doc sach, thuoc sach
va hang » van hang, va lang, va hanh
doi cuu » doi cua, doi cuoc
va nang » van nang, da nang, cam nang
cac thu » cach thuc, cac thoi
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
cuu tre » cua tre, cau tren, cau treo

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 (nguoi sach)) tu nang xa hoi. hieu va cac thu ((va hang) OR (va nang)) doi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (nguoi sach)) tu nang xa hoi. hieu va cac thu ((va hang) OR (va nang)) doi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (nguoi sach)) tu nang xa hoi. hieu va cac thu ((va hang) OR (va nang)) doi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (nguoi sach)) tu nang xa hoi. hieu va cac thu ((va hang) OR (va nang)) doi cuu tre*.