Perhaps you should try some spelling variations:
dieu cua » dieu tra
tu sach » thu sach, su sach, tu cach
te sach » toc sach
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va hoc » van hoc
va dan » va dao, va dau, va dap
ca dan » cac dan, ca 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 (te sach)) ky nang xa hoi. lieu va hoc nuoc ((va dan) or (ca dan)) dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang xa hoi. lieu va hoc nuoc ((va dan) OR (ca dan)) dieu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) ky nang xa hoi. lieu va hoc nuoc ((va dan) or (ca dan)) dieu cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) ky nang xa hoi. lieu va hoc nuoc ((va dan) or (ca dan)) dieu cua tre*.