Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
nganh cong » nhanh chong, thanh cong
sach nhanh » cach nhanh, sach nha, sach tranh
chong khi » khong khi, chong lai, chong li
chong hiv » among hiv, chong li, chong vi
cong khi » cong thai, khong khi, co khi
vu sach » vu bach, vu khach
su sach » so sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( vu sach nganh cong khi đong luc ) or ( su sach nhanh ((chong khi) OR (chong hiv)) đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( vu sach nganh cong khi đong luc ) OR ( su sach nhanh ((chong khi) OR (chong hiv)) đong luc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( vu sach nganh cong khi đong luc ) or ( su sach nhanh ((chong khi) OR (chong hiv)) đong luc ))*".