This is really one of the best sites for science news and abstracts. Most of the articles are readable though some may require in-depth knowledge of the field to be of much use. New Articles cost money but there are also free ones. Love it.
This is the website of the hugely influential American Association for the Advancement of Science (AAAS) 'Science' journal. It hosts various collections both of both freely available and of purchasable scientific articles from its journals. The journal is known for honoring some of America's foremost scientists with short terms as its editor. The site's homepage is well worth visiting. Many of the articles are unnecessarily riddled with jargon. Fortunately, when very important articles are especially difficult to read, they may be accompanied by several levels of explanatory articles.
This is the official site of Science magazine, one of the foremost science journals in the world. Although you have to pay to get access to most of the newer articles, you can register for free to get access to older articles (articles published more than a year ago and since 1997).