Perhaps you should try some spelling variations:
truong doi » truong dai, trong doi, truong hoi
so sach » so sanh, bo sach, co sach
doi cua » dai cua, hoi cua
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
ty nang » ky nang, ty xang, ty hang
co hoi » co hoc, co loi
tu xa » tu xay, tu va, tu ma
te xa » te va
o hoi » o hoc, o hai, o hoa

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 ty nang ((o hoi) OR (co hoi)). hieu va cac ((tu xa) or (te xa)) truong doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang ((o hoi) OR (co hoi)). hieu va cac ((tu xa) OR (te xa)) truong doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang ((o hoi) OR (co hoi)). hieu va cac ((tu xa) or (te xa)) truong doi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty nang ((o hoi) OR (co hoi)). hieu va cac ((tu xa) or (te xa)) truong doi cua tre*.