Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
dang ha » dong ha, dung ha, lang ha
van lam » van nam
cua tre » cua te, cuu tre, cua triet
y dang » ky dang, 2 dang, _ dang
ha hoi » hoa hoi, ha noi, xa hoi
bac va » bac ha, bao va, tac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y dang ha hoi. hieu van lam ((((bac va) or (ban va))) or (tuc va)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y dang ha hoi. hieu van lam ((((bac va) OR (ban va))) OR (tuc va)) thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y dang ha hoi. hieu van lam ((((bac va) or (ban va))) or (tuc va)) thanh dai cua tre*.