Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
phan duc » pham duc, phan tu, phan dau
vai cua » dai cua, hai cua, lai cua
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma

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 (toc sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) phan duc van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) phan duc van hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) phan duc van hanh vai cua tre*".