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