Perhaps you should try some spelling variations:
te sach » toc sach
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cac toc » cac toi, cac nuoc, cac thoi
hieu ve » hieu va, hieu van
cac tuc » cac tu, cac tac, cac nuoc
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 y nang ((x hoi) OR (o hoi)). hieu ve ((cac tuc) or (cac toc)) va danh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((x hoi) OR (o hoi)). hieu ve ((cac tuc) OR (cac toc)) va danh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((x hoi) OR (o hoi)). hieu ve ((cac tuc) or (cac toc)) va danh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((x hoi) OR (o hoi)). hieu ve ((cac tuc) or (cac toc)) va danh vi cua tre*.