Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thu sach » tu sach, thuat sach, thuoc sach
truc va » thuc va, thuc vat, trung va
van cau » van dau, van hau, van chat
te sach » toc sach
nang co » nang cao, nang doc, nang noi
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
vi cua » vai cua, di cua

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 (thu sach)) ky nang co hoi. hieu van cau ((duc va) or (truc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (thu sach)) ky nang co hoi. hieu van cau ((duc va) OR (truc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (thu sach)) ky nang co hoi. hieu van cau ((duc va) or (truc va)) hanh vi cua tre*.