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

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 (nang luc)) van hanh de ((cua tre) or (cuu 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 (nang luc)) van hanh de ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu van ((hau luc) or (nang luc)) van hanh de ((cua tre) or (cuu tre))*.