Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
chong khi » khong khi, chong hiv, chong lai
nganh co » nganh cong, nganh hoa, nganh y
can nhan » chan nhan, ca nhan, van nhan
cong khi » cong thai, khong khi, cong ha
so sach » so sanh, bo sach, co sach
su can » su van, su cao, tu can

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 nganh co khi đong luc ) OR ( su can nhan ((chong khi) OR (cong khi)) đong luc ))~.
• Adding a wildcard symbol may retrieve word variants: (( so sach nganh co khi đong luc ) or ( su can nhan ((chong khi) or (cong khi)) đong luc ))*.