Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
thi cua » thai cua, thi cuc, tri cua
cac tac » cac bac, cac dac, cac tai
cac toc » cac toi, cac nuoc, cac thoi
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao

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