Oxygen exists in two gaseous (dioxygen and ozone) and six solid allotropic modifications. An additional allotropic modification of oxygen, the cyclooctaoxygen, was predicted to exist in 1990. The fi……続きを見る
Drugs have played a major role in treatment for thousands of years. Most of us have taken, or will take, medicines at some time in our lives to cure, prevent, delay or mask the symptoms of ill healt……続きを見る
