Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
hoc sac » hoc sach, hoc cac, hoc mac
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
va cua » va chua, via cua, ma cua
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky nang xa hoi. ((hieu va) or (hieu van)) cam xuc va danh ((va cua) OR (ca cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky nang xa hoi. ((hieu va) OR (hieu van)) cam xuc va danh ((va cua) OR (ca cua)) tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sac ky nang xa hoi. ((hieu va) or (hieu van)) cam xuc va danh ((va cua) OR (ca cua)) tu".
• Adding a wildcard symbol may retrieve word variants: hoc sac ky nang xa hoi. ((hieu va) or (hieu van)) cam xuc va danh ((va cua) OR (ca cua)) tu*.