Perhaps you should try some spelling variations:
thanh ca » thanh cha, thanh cac, thanh ha
so sach » so sanh, bo sach, co sach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
duoc va » duc va, duoc ma, duong va
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va nam » van nam, ha nam, va nay
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang cao hoi. hieu va nam ((duoc va) OR (nuoc va)) thanh ca cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang cao hoi. hieu va nam ((duoc va) OR (nuoc va)) thanh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach y nang cao hoi. hieu va nam ((duoc va) OR (nuoc va)) thanh ca cua tre*.