Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
ban thanh » ban hanh, ban hang
nam duoc » nam thuoc, da duoc, dat duoc
toan cua » than cua, tan cua, doanh cua
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
lam duc » lam duoc, pham duc, lam dung
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
o hai » co hai, so hai, o lai
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: su sach ky nang ((x hoi) or (o hai)). hieu van ((lam duc) or (nam duoc)) ban thanh toan cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((x hoi) OR (o hai)). hieu van ((lam duc) OR (nam duoc)) ban thanh toan cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) or (o hai)). hieu van ((lam duc) or (nam duoc)) ban thanh toan cua tre*.