Molecular dynamics simulations are performed to observe the evolutions of 5~(12) and 5~(12)6~2 cage-like water clusters ......

This special issue, “NGOs and Social Transition in China,” contains seven articles answering the following two questio......

Tourism is rapidly becoming a sustainable pathway toward economic prosperity for host countries and communities. Recent ......

<正> American presidents get millions of letters every year.So far,more people are writing to President Clinton than wro......

【正】汽车是美国生活的重要组成部分。汽车使美国成了"汽车轮子上的国家",它也帮助美国成为现在的样子。汽车在美国......