Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve phan » va phan, ke phan, ve phat
duc van » duc tan, duc manh, duc phan
hanh va » hang va, hanh vi
va cua » va chua, via cua, ca cua
cua te » cua tu

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 ((duc van) OR (duc va)) hanh va cua te~.
• 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 ((duc van) OR (duc va)) hanh va cua te*.
• 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 ((duc van) OR (duc va)) hanh va cua te*".