Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
tham thuc » nham thuc, pham thuc, tam thuc
dang van » hoang van, hang va
tang van » hoang van, trong van, tang luan
thuc ban » thuoc ban, thuc dan, thu ban
thanh le » thinh le, thanh ve, thanh de
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
le cua » ly cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty ((dang van) or (tang van)) hoi. hieu ve tham thuc ban thanh le cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((dang van) OR (tang van)) hoi. hieu ve tham thuc ban thanh le cua vat.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((dang van) or (tang van)) hoi. hieu ve tham thuc ban thanh le cua vat*.