Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh ve » hanh ve, thanh va, thanh vien
va trien » va truyen, va thiet, va tuyen
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
sach ty » sach tu, sach thu, xach tay
duc ban » duc tan, duc van, dua ban
cuu tre » cua tre, cau tren, cau treo
ve pham » vi pham, v pham, ve phan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach y)) nang xa hoi. hieu ve pham duc ban thanh ve ((cuu tre) OR (va trien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) OR (sach y)) nang xa hoi. hieu ve pham duc ban thanh ve ((cuu tre) or (va trien))~".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) OR (sach y)) nang xa hoi. hieu ve pham duc ban thanh ve ((cuu tre) or (va trien))*.