Perhaps you should try some spelling variations:
thien van » thi van
luat duoc » luat tuc
toc sach » hoc sach, doc sach, thuoc sach
dinh vai » dinh van, dinh vi, dinh va
hieu van » hieu va, lieu va, hieu ve
vai cua » dai cua, hai cua, lai cua
va dinh » van dinh, va kinh, va tinh
duoc va » nuoc va, duc va, duoc ma
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky lang xa hoi. ((hieu van) OR (thien van)) luat duoc va dinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky lang xa hoi. ((hieu van) OR (thien van)) luat duoc va dinh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky lang xa hoi. ((hieu van) OR (thien van)) luat duoc va dinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky lang xa hoi. ((hieu van) OR (thien van)) luat duoc va dinh vai cua tre*.