Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va
va hanh » van hanh, va thanh, va danh
hoi cua » hoi chuc
cac co » cac cong
co va » co ma, do va, so va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cac co va hanh ((hoi cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cac co va hanh ((hoi cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cac co va hanh ((hoi cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cac co va hanh ((hoi cua) or (dai cua)) tre*.