Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cac lop » cac hop, cac loai
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
te sach » toc sach
lop va » lap va, hop va, nop va
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: ((su sach) or (te sach)) ky nang xa hoi. ((hieu vien) OR (thieu nien)) cac lop va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (te sach)) ky nang xa hoi. ((hieu vien) OR (thieu nien)) cac lop va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (te sach)) ky nang xa hoi. ((hieu vien) OR (thieu nien)) cac lop va hanh vi cua tre*".