Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
luc van » luoc van, duc van, luc va
luu van » cuu van, luan van, luu hanh
cua tre » cua te, cuu tre, cua triet
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: ((thuoc sach) or (su sach)) ky tang ma hoa. hieu van nam ((luc van) OR (luu van)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (su sach)) ky tang ma hoa. hieu van nam ((luc van) OR (luu van)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (su sach)) ky tang ma hoa. hieu van nam ((luc van) OR (luu van)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (su sach)) ky tang ma hoa. hieu van nam ((luc van) OR (luu van)) hanh vi cua tre*.