Perhaps you should try some spelling variations:
ban thanh » ban hanh
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
van lam » van nam
lam qua » lam cua, nam qua, lam quang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 hoi. hieu van lam qua ((((ban thanh) or (ban hang))) or (ngan hang)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu van lam qua ((((ban thanh) OR (ban hang))) OR (ngan hang)) dai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu van lam qua ((((ban thanh) or (ban hang))) or (ngan hang)) dai cua tre*.