Perhaps you should try some spelling variations:
sinh thai » dinh thi
nhanh thi » nhanh thai, nhanh thuc, nhan tai
tu sach » thu sach, su sach, te sach
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, pham duc, nam duoc
hieu ve » hieu va, hieu van
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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 o hai. hieu ve ((cam duc) OR (cao duc)) van ((nhanh thi) or (sinh thai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang o hai. hieu ve ((cam duc) OR (cao duc)) van ((nhanh thi) OR (sinh thai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hai. hieu ve ((cam duc) OR (cao duc)) van ((nhanh thi) or (sinh thai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang o hai. hieu ve ((cam duc) OR (cao duc)) van ((nhanh thi) or (sinh thai)) cua tre*.