Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat 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 danh » va dinh, va hanh, dia danh
tai cua » thai cua, tai cuc, tri cua
va dan » ca dan, va dao, va dau
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: ((thuoc sach) or (dac sac)) ky nang xa hoi. hieu van nam tuc ((va danh) OR (va dan)) tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (dac sac)) ky nang xa hoi. hieu van nam tuc ((va danh) OR (va dan)) tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (dac sac)) ky nang xa hoi. hieu van nam tuc ((va danh) OR (va dan)) tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (dac sac)) ky nang xa hoi. hieu van nam tuc ((va danh) OR (va dan)) tai cua te*.