Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
luat duoc » luat tuc
hieu van » hieu va, thien van, lieu va
thanh va » thanh van, hanh va, thanh ha
su sach » so sach, vu sach
lam xuc » cam xuc, lam duoc
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((nang ma) or (tang ma)) hoi. hieu van ((lam xuc) or (luat duoc)) ban thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ma) OR (tang ma)) hoi. hieu van ((lam xuc) OR (luat duoc)) ban thanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang ma) or (tang ma)) hoi. hieu van ((lam xuc) or (luat duoc)) ban thanh va cua tre*.