Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh duc » thach duc, than duc, thinh duc
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh tai, hanh van
hanh va » hang va, hanh vi
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
lang ha » long ha
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((nang xa) or (lang ha)) hoi. hieu van thanh duc va ((hanh vai) or (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang ha)) hoi. hieu van thanh duc va ((hanh vai) OR (hanh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (lang ha)) hoi. hieu van thanh duc va ((hanh vai) or (hanh va)) cua tre*.