Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
tai cua » thai cua, tai cuc, tri cua
xuc va » tuc va, luc va, xac va
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: ((toc sach) or (dac sac)) ky nang xa hoi. hieu van cam ((xuc va) OR (duc va)) hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (dac sac)) ky nang xa hoi. hieu van cam ((xuc va) OR (duc va)) hanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (dac sac)) ky nang xa hoi. hieu van cam ((xuc va) OR (duc va)) hanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (dac sac)) ky nang xa hoi. hieu van cam ((xuc va) OR (duc va)) hanh tai cua te*.