Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
duc ban » duc tan, duc van, dua ban
lam duc » lam duoc, pham duc, nam duoc
sach ky » sac ky, sach y, sach ty
van lam » van nam
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet
cu tre » cu tren, cuu tre, cu tri

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang xa) or (nang ma)) hoi. hieu van lam duc ban thanh van ((cu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (nang ma)) hoi. hieu van lam duc ban thanh van ((cu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang xa) or (nang ma)) hoi. hieu van lam duc ban thanh van ((cu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) or (nang ma)) hoi. hieu van lam duc ban thanh van ((cu tre) OR (cua tre))*.