Perhaps you should try some spelling variations:
dang nganh » duong nganh, dung ngan, dang hanh
nganh xay » nganh mac, nganh y, nganh ma
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
ngan ky » nganh ky, nhan ky, ngan hay
so dang » su dang, so dan, so dung
xay chi » xay chen
ky khi » ky thi, ly khi

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: (( ((so sach) OR (co sach)) ngan ky khi đong luc ) OR ( so dang nganh xay chi đong luc ))~.
• Adding a wildcard symbol may retrieve word variants: (( ((so sach) or (co sach)) ngan ky khi đong luc ) or ( so dang nganh xay chi đong luc ))*.