Perhaps you should try some spelling variations:
thien van » thi van
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cac tuc » cac toc, cac tu, cac tac
cua tre » cua te, cuu tre, cua triet
vu nang » vuc nang, va nang, vu dang
so sanh » do sanh
tuc va » thuc va, truc va, tuc xa
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 sanh)) vu nang x hoi. ((lieu va) or (thien van)) cac tuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) vu nang x hoi. ((lieu va) OR (thien van)) cac tuc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) vu nang x hoi. ((lieu va) or (thien van)) cac tuc va hanh vi cua tre*.