Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
nang xa » nang x, lang xa, nang ma
hieu vi » hieu voi, hieu va, hien vi
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang xa hoi. ((hieu vi) OR (hieu ve)) pham duc van hanh vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang xa hoi. ((hieu vi) OR (hieu ve)) pham duc van hanh vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang xa hoi. ((hieu vi) OR (hieu ve)) pham duc van hanh vi cuu tre*.