Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
nam thuc » nam thuoc, am thuc, nam thu
quan nam » quang nam, xuan nam, quan am
dang xay » dang van, van xay
lai cua » dai cua, hai cua, lai chau
dan lai » dan loai, dan lap, dan lat
thuc va » thuc vat, thuc dan, thuc day
so sach » so sanh, bo sach, hoc sach
lang xa » lang ha, lang van
co sach » bo sach, cuon sach, hoc sach
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) OR (co sach)) y ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) y ((lang xa) OR (dang xay)) hoi. hieu quan nam thuc va dan lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (co sach)) y ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan lai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (co sach)) y ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan lai cua tre*.