Since: 3.7
SAO/NASA Astrophysics Data System is an online database of over eight million astronomy and physics papers from both peer reviewed and non-peer reviewed sources. Abstracts are available free online for almost all articles, and full scanned articles are available in Graphics Interchange Format (GIF) and Portable Document Format (PDF) for older articles (Wikipedia).
To use this feature, choose BibTeX → New entry.... In the lower part, there is the box "ID-based entry generator". In the field "ID type", "SAO/NASA Astrophysics Data System" can be selected (see screenshot below). Select the field "ID" and enter the SAO/NASA Astrophysics Data System ID here (e.g., 2013Sci...339..671W) and press Enter to generate an entry based on the Id. You can also click on "Generate". The found entry is opened in an entry editor. In case an error occurs, a popup is shown.