Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
te sach » toc sach
hieu va » lieu va, hieu qua
cac thu » cach thuc, cac thoi
cuu tre » cua tre, cau tren, cau treo
cac tu » cach tu, cac du, tac tu
ca ban » cua ban, can ban, cac ban
va cuu » va cau, va chu, va huu
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (te sach)) ky nang x hoi. hieu va ((cac tu) OR (cac thu)) ca ban va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) ky nang x hoi. hieu va ((cac tu) OR (cac thu)) ca ban va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (te sach)) ky nang x hoi. hieu va ((cac tu) OR (cac thu)) ca ban va cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) ky nang x hoi. hieu va ((cac tu) OR (cac thu)) ca ban va cuu tre*.