http://www.epa.gov/ncepihom/ National Service Center for Environmental Publications提供的是美国环境保护总署(EPA)出版物。可以通过EPA出版号或题名检索EPA National Publications Catalog。
http://herald.iop.org/conmat/m163/exl//link/550 eprintweb.org is THE quickest and easiest way to track e-prints in your area. It's updated daily and is free to read. 可以下载全文。查找后部分可能无法通过点击‘full text'下载,但可以先点击‘abstract’,进入后再点右侧‘PDF'下载。