Perhaps you should try some spelling variations:
sach khanh » sach tranh, sach kinh, sach danh
sach nganh » sach ngan, sach tranh, cac nganh
phong khi » phong thi, phong kham, phong khoa
khong khi » khong he
nganh co » nganh cong, nganh hoa, nganh y
su sach » vu sach
so sach » so sanh, bo sach, co sach

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 nganh co khi đong luc ) OR ( so sach khanh ((phong khi) OR (khong khi)) đong luc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( su sach nganh co khi đong luc ) or ( so sach khanh ((phong khi) OR (khong khi)) đong luc ))~".
• Adding a wildcard symbol may retrieve word variants: (( su sach nganh co khi đong luc ) or ( so sach khanh ((phong khi) OR (khong khi)) đong luc ))*.