Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
thanh di » thanh doi, thanh de, thanh do
hieu van » hieu va, thien van, lieu va
dau tren » dau tien, dat tren, dau tieng
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
nam duc » nam duoc, pham duc, nam thuc
duc van » duc va, duc tan, duc manh
nang xa » nang x, nang ma, mang xa
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang xa) or (lang xa)) hoi. hieu van nam duc van thanh di ((cuu tre) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang xa) OR (lang xa)) hoi. hieu van nam duc van thanh di ((cuu tre) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang xa) or (lang xa)) hoi. hieu van nam duc van thanh di ((cuu tre) or (dau tren))*.