Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
va dinh » van dinh, va kinh, vu dinh
thi cua » thai cua, thi cuc, tri cua
va tinh » may tinh
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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 v nang xa hoi. hieu va ((cac tuc) or (cac tac)) ((va dinh) OR (va tinh)) thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang xa hoi. hieu va ((cac tuc) OR (cac tac)) ((va dinh) OR (va tinh)) thi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang xa hoi. hieu va ((cac tuc) or (cac tac)) ((va dinh) OR (va tinh)) thi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang xa hoi. hieu va ((cac tuc) or (cac tac)) ((va dinh) OR (va tinh)) thi cua tre*.