Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
cam duc » cam xuc, pham duc, nam duoc
cao duc » dao duc, cao suc, giao duc
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky

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) OR (sac ky)) nang xa hoi. hieu van ((cam duc) or (cao duc)) ban thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang xa hoi. hieu van ((cam duc) OR (cao duc)) ban thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang xa hoi. hieu van ((cam duc) or (cao duc)) ban thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang xa hoi. hieu van ((cam duc) or (cao duc)) ban thanh dai cua tre*.