Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
tu nong » tu dong, tu cong, tu tong
nong xa » song xa, dong xa, nong va
hieu ve » hieu va, hieu van
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
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: ((so sach) or (co sach)) tu nong xa hoi. hieu ve cac ((duc va) or (tuc xa)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) tu nong xa hoi. hieu ve cac ((duc va) OR (tuc xa)) hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (co sach)) tu nong xa hoi. hieu ve cac ((duc va) or (tuc xa)) hanh va cua tre*.