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