Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
te sach » toc sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
va cam » va cham, va cac, va cao
xac va » tac va, ac va, bac va
luc va » duc va, tuc va, loc va
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: te sach ((y nang) OR (ky nang)) x hoi. hieu va cam ((xac va) or (luc va)) vanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y nang) OR (ky nang)) x hoi. hieu va cam ((xac va) OR (luc va)) vanh dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y nang) OR (ky nang)) x hoi. hieu va cam ((xac va) or (luc va)) vanh dai cua tre*".