Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nhan luc » nang luc
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hau luc » hau loc, cau luc, hieu luc
kem cua » em cua, keo cua, diem cua
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky nang xa hoi. hieu van ((hau luc) or (nhan luc)) van hanh kem cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu van ((hau luc) OR (nhan luc)) van hanh kem cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu van ((hau luc) or (nhan luc)) van hanh kem cua tre*.