Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
hai cua » thai cua, dai cua, hoi cua
duc van » duc va, duc tan, duc manh
dua ban » dia ban, cua ban, qua ban
van cam » van nam, van lam, van cau
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
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: so sach y ((nang xa) or (nang ma)) hoi. hieu van cam ((dua ban) or (duc van)) thanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang xa) OR (nang ma)) hoi. hieu van cam ((dua ban) OR (duc van)) thanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang xa) or (nang ma)) hoi. hieu van cam ((dua ban) or (duc van)) thanh hai cua tre*.