Perhaps you should try some spelling variations:
te sach » toc sach
cao hoi » cau hoi, co hoi, tao hoi
cao hoc » cho hoc, chat hoc
hieu va » lieu va, hieu qua
nam duc » nam duoc, pham duc, nam thuc
duc van » duc va, duc tan, duc manh
minh vi » minh voi, dinh vi, minh 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
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((cao hoi) OR (((cao hoc) OR (co hoc)))). hieu va nam duc van minh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((cao hoi) or (((cao hoc) OR (co hoc)))). hieu va nam duc van minh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((cao hoi) or (((cao hoc) OR (co hoc)))). hieu va nam duc van minh vi cua tre*.