Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
te sach » toc sach
sach tu » sach thu, cach tu, sach ty
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
hieu va » lieu va, hieu qua
tu nong » tu dong, tu cong, tu tong
tuc va » thuc va, truc va, tuc xa
nong x » nong xa, nang x, nong e
x hoi » xa hoi, o hoi, x ho

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 tu nong x hoi. hieu va cac ((duc va) or (tuc va)) thanh dai ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu nong x hoi. hieu va cac ((duc va) OR (tuc va)) thanh dai ((cuu tre) OR (cua tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tu nong x hoi. hieu va cac ((duc va) or (tuc va)) thanh dai ((cuu tre) OR (cua tre))*".