Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
tang van » hoang van, trong van, tang luan
dang van » hoang van, hang va
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
hanh va » hang va, hanh vi
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
va hoa » van hoa, va hoc, ma hoa

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: su sach ky ((tang van) OR (dang van)) hoc. ((hieu ve) OR (hieu van)) cham thuc va hanh va hoa viet~.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((tang van) or (dang van)) hoc. ((hieu ve) or (hieu van)) cham thuc va hanh va hoa viet*.