Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
quoc ban » quoc bao, quoc lan, quoc quan
hieu van » hieu va, thien van, lieu va
duoc ban » duc ban, buoc ban, duoc bat
vai cua » dai cua, hai cua, lai cua
van lam » van nam
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 lam ((duoc ban) or (quoc ban)) thanh vai 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 lam ((duoc ban) OR (quoc ban)) thanh vai 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 lam ((duoc ban) or (quoc ban)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang xa hoi. hieu van lam ((duoc ban) or (quoc ban)) thanh vai cua tre*.