Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
xuc van » duc van, vuc van, xuc ban
luc van » luoc van, luu van, duc van
hanh va » hang va, hanh vi
su viet » so viet

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