Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
y nang » ky nang, ly nang, v nang
xuc va » tuc va, luc va, xac va
te cua » tue cua, le cua, de cua
cua tu » cua tuc, cua su, cua cu

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 y nang xa hoi. hieu van cac ((xuc va) or (duc va)) kinh te cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang xa hoi. hieu van cac ((xuc va) OR (duc va)) kinh te cua tu.
• Adding a wildcard symbol may retrieve word variants: su sach y nang xa hoi. hieu van cac ((xuc va) or (duc va)) kinh te cua tu*.