Perhaps you should try some spelling variations:
hieu cac » hieu luc, hieu va, hieu van
van dinh » van minh, van dich, va dinh
hien cac » thien cac, vien cac, dien cac
tu sach » thu sach, su sach, tu cach
dinh va » dinh van, dinh ve, tinh va
lao van » dao van, cao van, lo van
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
te sach » toc sach
va cua » va chua, via cua, ca cua

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: ((tu sach) OR (te sach)) ky nang xa hoi. hieu ((hien cac) OR (hieu cac)) lao van dinh va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky nang xa hoi. hieu ((hien cac) OR (hieu cac)) lao van dinh va cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang xa hoi. hieu ((hien cac) OR (hieu cac)) lao van dinh va cua tre*.