Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
su sach » vu sach
so sach » so sanh, bo sach, co sach
cac tac » cac toc, cac bac, cac dac
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
tac va » tac da, tac xa, tuc va
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: ((su sach) or (so sach)) y nang x hoi. ((hieu van) or (thien van)) cac tac va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) y nang x hoi. ((hieu van) OR (thien van)) cac tac va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) y nang x hoi. ((hieu van) or (thien van)) cac tac va hanh vi cua tre*.