Perhaps you should try some spelling variations:
hanh sinh » hanh tinh, hanh dinh, hinh sinh
hieu van » hieu va, thien van, lieu va
sinh cua » manh cua, dinh cuu, sinh va
toc sach » hoc sach, doc sach, thuoc sach
van cac » van hac, van cau, van bac
xay hoi » xa hoi, tay hoi, cay phoi
xuc va » duc va, tuc va, luc va
ky van » ly van, ty van, ky va
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: ((te sach) OR (toc sach)) ky van xay hoi. hieu van cac ((xuc va) or (thuc vat)) hanh sinh cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky van xay hoi. hieu van cac ((xuc va) OR (thuc vat)) hanh sinh cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky van xay hoi. hieu van cac ((xuc va) or (thuc vat)) hanh sinh cua tu".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky van xay hoi. hieu van cac ((xuc va) or (thuc vat)) hanh sinh cua tu*.