Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van ban
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
van anh » van thanh, tuan anh, van minh
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.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky nang xa hoi. hieu ve pham duc ((van hanh) OR (van anh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang xa hoi. hieu ve pham duc ((van hanh) OR (van anh)) vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang xa hoi. hieu ve pham duc ((van hanh) OR (van anh)) vi cua tre*".