Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
thuy va » thuy van, thuc va, thue va
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
cau tre » cau tren, cau treo, cau tra
di cau » da cau, diem cau

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 x) or (nang ma)) hoi. hieu van thanh thuy va danh di cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang x) OR (nang ma)) hoi. hieu van thanh thuy va danh di cau tre*.