Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cham truc » cau truc, nham thuc, pham thuc
thanh di » thanh doi, thanh de, thanh do
truc ban » thuc ban, truc dan, truc van
co sach » bo sach, cuon sach, hoc sach
so sanh » do sanh
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
di cua » dai cua, doi cua, de cua
cua te » cua tu

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: ((co sach) OR (so sanh)) vu ((nang ma) OR (sang ma)) hoi. hieu vu cham truc ban thanh di cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) or (so sanh)) vu ((nang ma) OR (sang ma)) hoi. hieu vu cham truc ban thanh di cua te~".
• Adding a wildcard symbol may retrieve word variants: ((co sach) or (so sanh)) vu ((nang ma) OR (sang ma)) hoi. hieu vu cham truc ban thanh di cua te*.