Perhaps you should try some spelling variations:
vat danh » va danh, van danh, luat danh
cau thuc » cau truc, cuu thuc, can thuc
hieu van » hieu va, thien van, lieu va
tang ma » mang may, tang van
sach ly » sach y, sach lo, sach ty
van cau » van dau, van hau, van chat
hang ma » hang va, hang ca, nang ma
keo cua » keo sua, khoe cua, cheo cua
kho cua » khoe cua, khi cua, cho cua
tu sach » thu sach, su sach, te sach

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly ((hang ma) OR (tang ma)) hoi. hieu van cau thuc vat danh ((keo cua) OR (kho cua)) viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly ((hang ma) or (tang ma)) hoi. hieu van cau thuc vat danh ((keo cua) OR (kho cua)) viet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ly ((hang ma) or (tang ma)) hoi. hieu van cau thuc vat danh ((keo cua) OR (kho cua)) viet*.