Perhaps you should try some spelling variations:
cao trung » cao truong, tao trung, bao trung
nuoc sach » nguoi sach, hoc sach, cuoc cach
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va ban » van ban, va bao
va cao » va cac, va co, va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (nuoc sach)) ky lang xa hoi. lieu va cao trung ((va ban) OR (va bai)) thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (nuoc sach)) ky lang xa hoi. lieu va cao trung ((va ban) OR (va bai)) thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (nuoc sach)) ky lang xa hoi. lieu va cao trung ((va ban) OR (va bai)) thai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (nuoc sach)) ky lang xa hoi. lieu va cao trung ((va ban) OR (va bai)) thai cua tre*.