Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh cac » hanh cac, thanh bac, thanh ca
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
mai hoi » mai khoi, dai hoi, lai hoi
nam duc » nam duoc, pham duc, nam thuc
duc ban » duc tan, duc van, dua ban
cac cua » cach cua, cac qua, ca cua
y nang » ky nang, ly nang, v nang
cua te » cua tu

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) or (co sach)) y nang mai hoi. hieu van nam duc ban thanh cac cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) y nang mai hoi. hieu van nam duc ban thanh cac cua te.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (co sach)) y nang mai hoi. hieu van nam duc ban thanh cac cua te*.