Perhaps you should try some spelling variations:
thien van » thi van
ban hanh » ban hang
hanh va » hang va, hanh vi
duc ban » duc tan, duc van, dua ban
dau duc » dao duc, dang duc, dau nuoc
van dau » van dao, phan dau
sach ky » sac ky, sach kem, sach hay
sach ty » sach tu, sach thu, xach tay
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) or (((sach ty) OR (sach y)))) nang x hoi. thien van dau duc ban hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (((sach ty) OR (sach y)))) nang x hoi. thien van dau duc ban hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (((sach ty) OR (sach y)))) nang x hoi. thien van dau duc ban hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (((sach ty) OR (sach y)))) nang x hoi. thien van dau duc ban hanh va cua tre*.