Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
nganh cong » nhanh chong, thanh cong
ngan cong » nganh nong, ngan hang, van cong
phan cong » thanh cong
cong khi » cong thai, khong khi, co khi
so sach » so sanh, bo sach, co sach
vu sach » vu bach, su sach, vu khach

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