Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su triet » su viet, su tien, ve triet
thanh va » thanh van, hanh va, thanh ha
thuc ban » thuoc ban, thuc dan, thu ban
nam thuc » nam thuoc, am thuc, nam thu
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao

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 ((nang x) OR (nang ma)) hoi. ((hieu ve) OR (hieu va)) nam thuc ban thanh va su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang x) or (nang ma)) hoi. ((hieu ve) OR (hieu va)) nam thuc ban thanh va su triet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang x) or (nang ma)) hoi. ((hieu ve) OR (hieu va)) nam thuc ban thanh va su triet*.