Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cao duoc » tao duoc, co duoc, cao duc
vanh dai » van dai, vanh tai, lanh dao
tu nong » tu dong, tu cong, tu tong
nong xa » song xa, dong xa, nong va
qua cao » qua cac, qua ca, qua cai
duoc xa » duoc ma, duoc va, duoc ha
xa vanh » xa vinh, xa van, xa thanh
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) tu nong xa hoi. hieu qua cao duoc xa vanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tu nong xa hoi. hieu qua cao duoc xa vanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) tu nong xa hoi. hieu qua cao duoc xa vanh dai cua tre*.