Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
nganh cong » nhanh chong, thanh cong
toc sach » hoc sach, doc sach, thuoc sach
tien van » thien van, trien van, tien va
cong he » cong che, cong ha, cong de
tin va » tien va, tinh va, tin vao
thong » trong

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach nganh cong he thong ((tin va) or (tien van)) truyen thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach nganh cong he thong ((tin va) OR (tien van)) truyen thong.
• Adding a wildcard symbol may retrieve word variants: toc sach nganh cong he thong ((tin va) or (tien van)) truyen thong*.