Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
van cac » van hac, van cau, van bac
xac va » tac va, ac va, bac va
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty xang xa hoi. hieu van cac ((xac va) or (duc va)) hanh ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty xang xa hoi. hieu van cac ((xac va) OR (duc va)) hanh ((vi cua) OR (di cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty xang xa hoi. hieu van cac ((xac va) or (duc va)) hanh ((vi cua) OR (di cua)) tre*".