Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thu sach » thuat sach, thuoc sach, thu hoach
thi cua » thai cua, thi cuc, tri cua
van dat » van dao, van dau, dan dat
tu sach » su sach, te sach, tu cach
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dap
va dau » va dao
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (thu sach)) ky lang xa hoi. hieu van dat nuoc ((va dan) or (va dau)) thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky lang xa hoi. hieu van dat nuoc ((va dan) OR (va dau)) thi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky lang xa hoi. hieu van dat nuoc ((va dan) or (va dau)) thi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky lang xa hoi. hieu van dat nuoc ((va dan) or (va dau)) thi cua tre*.