Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
sach thu » sach thieu, sach tham, cach thuc
hai cua » thai cua, dai cua, hoi cua
dau hai » dai hai, dau ha, cau hai
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van dam
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va dau » va dao

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 thue)) nang xa hoi. hieu ((van cam) OR (van cau)) thuc va dau hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach thu) OR (sach thue)) nang xa hoi. hieu ((van cam) OR (van cau)) thuc va dau hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach thu) or (sach thue)) nang xa hoi. hieu ((van cam) OR (van cau)) thuc va dau hai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach thu) or (sach thue)) nang xa hoi. hieu ((van cam) OR (van cau)) thuc va dau hai cua tre*.