Perhaps you should try some spelling variations:
ban xanh » ban hanh, ban anh, ban banh
quoc ban » quoc bao, quoc lan, quoc quan
tu sach » thu sach, su sach, te sach
xanh de » hanh de, xanh di, thanh de
vu kham » vu khanh
sach ky » sac ky, sach y, sach ty
vu cham » va cham, tu cham, qua cham
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky sang ((ma hoi) or (mai hoi)). hieu ((vu cham) or (vu kham)) quoc ban xanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ((ma hoi) OR (mai hoi)). hieu ((vu cham) OR (vu kham)) quoc ban xanh de cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ((ma hoi) or (mai hoi)). hieu ((vu cham) or (vu kham)) quoc ban xanh de cua tre*.