Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di 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: ((su sach) OR (toc sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) nhan thuc va hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (toc sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) nhan thuc va hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) nhan thuc va hanh vi cua tre*.