Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
ban hanh » ban hang
kho tang » cao tang
van hanh » van thanh, van anh, van ban
hieu van » hieu va, thien van, lieu va
van lam » van nam
lam xuc » cam xuc, lam duoc
tang ma » mang may, tang van
su sach » so sach, vu sach
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: ((hoc sach) or (su sach)) kho tang ma hoa. hieu van lam xuc ((van hanh) OR (ban hanh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (su sach)) kho tang ma hoa. hieu van lam xuc ((van hanh) OR (ban hanh)) va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (su sach)) kho tang ma hoa. hieu van lam xuc ((van hanh) OR (ban hanh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (su sach)) kho tang ma hoa. hieu van lam xuc ((van hanh) OR (ban hanh)) va cua tre*.