Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hang hoc » hang hoa, nang hoc, bang hoc
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
hieu ve » hieu va, hieu van
tai va » thai va, mai va, dai va
thuc » thu

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 ty hang hoc dan. hieu ve ((am thuc) or (nam thuoc)) van hanh ((tai va) or (tri va)) trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty hang hoc dan. hieu ve ((am thuc) OR (nam thuoc)) van hanh ((tai va) OR (tri va)) trien.
• Adding a wildcard symbol may retrieve word variants: te sach ty hang hoc dan. hieu ve ((am thuc) or (nam thuoc)) van hanh ((tai va) or (tri va)) trien*.