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
nam tuc » nam thuc, nam truc, nam tu
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cuc te » cua te, cuc thue, cuc tieu

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 nam tuc ((va hanh) OR (va danh)) tai cuc 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 nam tuc ((va hanh) OR (va danh)) tai cuc 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 nam tuc ((va hanh) OR (va danh)) tai cuc te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (dac sac)) ky nang xa hoi. hieu van nam tuc ((va hanh) OR (va danh)) tai cuc te*.