Perhaps you should try some spelling variations:
nhung chong » nhung cong, nhung phong, nhung phuong
thieu sach » chieu sach, hieu cach, theo sach
thien hach » thien thanh, hien hanh
tranh cua » doanh cua, manh cua
cua nhung » va nhung
chong bai » cuong bai, thong bai, chong lai
bai toan » bai tap
toan ban » van ban

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (thien hach)) - canh tranh cua nhung chong bai toan ban~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (thien hach)) - canh tranh cua nhung chong bai toan ban*.