Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
phan truc » phan thuc, phan trac, phan tu
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di 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 tang ma hoi. hieu luan phan truc ((ban hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ma hoi. hieu luan phan truc ((ban hanh) OR (van hanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ma hoi. hieu luan phan truc ((ban hanh) or (van hanh)) vi cua tre*.