Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va hoc » van hoc
va dau » va dao
dau de » dau ve, dai de, sau de
de cua » le cua, te cua, dieu cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu va hoc (nuoc OR duoc) va dau de cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang x)) hoi. hieu va hoc (nuoc OR duoc) va dau de cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang x)) hoi. hieu va hoc (nuoc OR duoc) va dau de cua tre*.