Perhaps you should try some spelling variations:
thien van » thi van
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
van am » van nam, van lam, van dam
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang x hoi. thien van am thuc ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang x hoi. thien van am thuc ((va hanh) OR (van hanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. thien van am thuc ((va hanh) or (van hanh)) vi cua tre*.