From the Science website:
"Science Classic is the NEWLY digitized fulltext archive of Science from AAAS featuring the collection of issues 1880–1996. It's the perfect complement to Science Online which covers 1997-today. Most important, Science Classic is fully integrated with the current content of Science Online making it easier to search the entire collection.
Each article's bibliographic citation, abstract, and references have been rekeyed in an interactive HTML file. This feature allows dynamic linking to: other Science articles across the complete collection, over 900 HighWire hosted journals providing toll-free access to thousands of articles, and fi nally the primary source or secondary databases through CrossRef/DOI, PubMed, and ISI Web of Science. As a result, Science Classic articles provide the end users with a new, more powerful searching tool and the flexible retrieval capabilities they’re used to.
From cover to cover, every page of the back issue file prior to 1997 has been scanned as a high-resolution PDF which offers the sharpest and highest quality text possible. The PDF files have been optimized for fast web transmission and excellent print quality. Each article is a fully searchable PDF."