Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thanh vi » thanh va, thanh ve, nhanh vi
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
ly ban » uy ban, ly bai
lo ban » co ban, lo van
thiet » thieu

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 cac ((ly ban) or (lo ban)) ((thanh vi) or (hanh vi)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu ve cac ((ly ban) OR (lo ban)) ((thanh vi) OR (hanh vi)) va thiet.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ve cac ((ly ban) or (lo ban)) ((thanh vi) or (hanh vi)) va thiet*.