Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
sach thu » sach thue, sach thieu, sach tham
cham duc » pham duc, cham soc, pham duy
cuu tre » cua tre, cau tren, cau treo
duc ban » duc tan, duc van, dua ban
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
mai hoi » mai khoi, dai hoi, lai hoi
sac ky » cac ky, sai ky
ma hoi » xa hoi, ma hoa, me hoi
va cuu » va cau, va chu, va huu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sac ky) or (sach thu)) tang ((ma hoi) or (mai hoi)). hieu vu cham duc ban thanh va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sac ky) OR (sach thu)) tang ((ma hoi) OR (mai hoi)). hieu vu cham duc ban thanh va cuu tre.
• Adding a wildcard symbol may retrieve word variants: te ((sac ky) or (sach thu)) tang ((ma hoi) or (mai hoi)). hieu vu cham duc ban thanh va cuu tre*.