Perhaps you should try some spelling variations:
sach cam » sach cap, mach cam, sach tham
su triet » su viet, ve triet
qua pham » quan pham, quy pham, qua cham
tinh ve » trinh ve, tinh ven, dinh ve
va tinh » may tinh
su sach » so sach, vu sach
tang ma » mang may, tang van
sang ma » nang ma, sang tao, mang may
su tien » su kien, su hien, tu tieng

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 cam ((sang ma) OR (tang ma)) hoi. hieu qua pham duc va tinh ve ((su triet) OR (su tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach cam ((sang ma) or (tang ma)) hoi. hieu qua pham duc va tinh ve ((su triet) OR (su tien))~".
• Adding a wildcard symbol may retrieve word variants: su sach cam ((sang ma) or (tang ma)) hoi. hieu qua pham duc va tinh ve ((su triet) OR (su tien))*.