Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
va phan » van phan, va phat, va phap
hanh va » hang va, hanh vi
duc van » duc va, duc tan, duc manh
ve phan » ke phan, ve phat, vi phan
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca 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 phan) OR (va phan)) duc van hanh va 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 phan) OR (va phan)) duc van hanh va 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 phan) OR (va phan)) duc van hanh va cua tre*".