Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
hanh te » hanh tu, hanh ve, hanh de
cam luc » cau luc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
te cua » tue cua, le cua, de cua

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 ve) or (hieu va)) ((cam luc) OR (cam xuc)) van hanh te cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. ((hieu ve) OR (hieu va)) ((cam luc) OR (cam xuc)) van hanh te cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. ((hieu ve) or (hieu va)) ((cam luc) OR (cam xuc)) van hanh te cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. ((hieu ve) or (hieu va)) ((cam luc) OR (cam xuc)) van hanh te cua tre*.