Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
khac tuc » khac phuc, khac tung, khac cuoc
hieu va » lieu va, hieu qua
va khac » va khao, va kha, vu khac
sach ky » sac ky, sach y, sach ty
va dang » van dang, va nang, da dang
va lang » va nang, hoa lang
dinh cu » dinh cuu, dinh chuc, dinh chau
cu tre » cu tren, cua tre, cuu tre
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc ((va dang) OR (va lang)) dinh cu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (o hoi)). hieu va khac tuc ((va dang) OR (va lang)) dinh cu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc ((va dang) OR (va lang)) dinh cu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) or (o hoi)). hieu va khac tuc ((va dang) OR (va lang)) dinh cu tre*.