Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
thai cua » than cua, tai cuc, tri cua
nang xa » nang x, lang xa, nang ma
nam tuc » nam thuc, nam truc, nam tu
tuc van » thuc van, truc van, tuc va
tai cua » tai cuc, tri cua, dai cua

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