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