Perhaps you should try some spelling variations:
hieu van » thien van, hieu ve
hoc sac » hoc sach, hoc cac, hoc mac
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
va danh » va dinh, va dan, va hanh
danh va » doanh va, hanh va, anh va
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
va cua » va chua, via cua, ca cua
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: hoc sac ky nang xa hoi. ((hieu va) or (((hieu van) OR (lieu va)))) cam xuc va danh va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky nang xa hoi. ((hieu va) OR (((hieu van) OR (lieu va)))) cam xuc va danh va cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sac ky nang xa hoi. ((hieu va) or (((hieu van) OR (lieu va)))) cam xuc va danh va cua te".
• Adding a wildcard symbol may retrieve word variants: hoc sac ky nang xa hoi. ((hieu va) or (((hieu van) OR (lieu va)))) cam xuc va danh va cua te*.