/images/1041385860215607387/1208557617434202252/dung-khoa-hoc-ky-thuat-den-tu-chan-quyen-2-chuong-43-nghien-cuu-phat-minh-moi-con-roi.txt?ex=65e3b7fd&is=65d142fd&hm=b784efbe5598da3bdef513d727f176b84e948bf11f6604c73586673f15c5f884&