Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
dinh du » dinh duc, dinh cu, dinh tu
su sach » so sach, vu sach
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
xuc va » tuc va, luc va, xac va
du cua » duy cua, dau cua, dum 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: su sach ty nang xa hoi. ((hieu ve) OR (hieu van)) cac ((xuc va) or (duc va)) dinh du cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. ((hieu ve) OR (hieu van)) cac ((xuc va) OR (duc va)) dinh du cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. ((hieu ve) OR (hieu van)) cac ((xuc va) or (duc va)) dinh du cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. ((hieu ve) OR (hieu van)) cac ((xuc va) or (duc va)) dinh du cua te*.