Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thuc van » thuc vat, thuc va, thuc hanh
thuc dan » thuc hanh, hoc dan, thuc vat
sach ty » sach y, sach tu, xach tay
xang xa » lang xa, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
va cau » van cau, va cac, va dau
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 ty) or (sach thu)) xang xa hoi. lieu va cau ((thuc van) OR (thuc dan)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) xang xa hoi. lieu va cau ((thuc van) OR (thuc dan)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) or (sach thu)) xang xa hoi. lieu va cau ((thuc van) OR (thuc dan)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach thu)) xang xa hoi. lieu va cau ((thuc van) OR (thuc dan)) hanh vi cua tre*.