Many of these resources are restricted to SAO and Harvard ID holders with PINs. Please follow these instructions to request a PIN.

• Aerospace & High Technology Database
  From Cambridge Scientific Abstracts; covers research in aeronautics, astronautics, and space sciences published in periodic literature, NASA and other U.S. government agencies' reports, and other institutional publications.
• ARIBIB - ARI Bibliographic Data Base for Astronomical References
  Astronomy and Astrophysics Abstracts online; coverage ends in 2000.
• arXiv.org e-Print archive
  ArXiv.org is a searchable full text database of preprints in the fields of physics, mathematics, non-linear science and computer science.
• Astrophysics Data System (ADS)
  Abstract service with links to full text when available. The above link is for CfA and Harvard affiliates to access ADS via the Library's proxy server.
• CDS Bibliographic Service
  Provides access to abstracts from Astronomy and Astrophysics, Astronomy and Astrophysics Supplement Series, New Astronomy, and Publications of the Astronomical Society of the Pacific.
• Chemical Abstracts
  PLEASE NOTE: This resource cannot be reached using your web browser. To access this resource, you must download a proprietary software client called Scifinder Scholar.
• Computing Reviews
  Published by the Association for Computing Machinery and hosted online by Reviews.com; provides full text reviews of the computer science literature, pointing readers to journal articles, books, technical reports, proceeding articles, and theses which the reviewers judge to be of high quality and relevance in their fields.
• CRC Handbook of Chemistry and Physics 89th Ed.
  Published by the CRC Press; the primary source for chemical and physical data. This online edition now allows for chemical structure searching, when a Java Applet is installed locally.
• Dissertations and Theses Full Text
  Indexes dissertations and masters' theses from most North American graduate schools as well as some European universities. Provides full text for most indexed dissertations from 1990-present.
• DOI Resolver
  Resolves DOIs (Digital Object Identifiers). More information about the Digital Object Identifier System.
• Encyclopedia of Astronomy and Astrophysics
  Published by Grove's Dictionaries; a database of over 3,000 articles commissioned by 800 professionals in the fields of astronomy and astrophysics.
• Engineering E-journal Search Engine
  Searches the full text of one hundred engineering e-journals.
• Factiva.com
  Contains over 8,000 business and news publications, including trade journals, newswires, and company and stock reports, most in full text.
• Google Scholar
  Google Scholar enables you to search for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research.
• Government science information search enginge
  Science.gov is a gateway to government science information and research that provides over 36 scientific databases and 200 million pages of information with just one query.
• IEEE Electronic Library (IEL)
  Includes access to the AbstractPlus records and full text published since 1988 and select content published since 1913 from: IEEE journals, transactions, and magazines; IEEE conference proceedings; IET journals; IET conference proceedings; IEEE published standards; IEEE Spectrum Magazine; and Proceedings of the IEEE.
• INSPEC
  The Institution of Electrical Engineers' (IEE) bibliographic database which covers the fields of physics, electronical engineering and electronics, computers and control engineering and information technology.
• LexisNexis Academic
  This resources offers access to more than 7,000 English language newspapers, newsletters, magazines, trade journals, wire services and broadcast transcripts.
• MathSciNet
  Covers material from Mathematical Reviews and Current Mathematical Publications, from 1940 to the present.
• Meteorological and Geophysical Abstracts
  Citations and abstracts from literature in the following fields: meteorology, climatology, atmospheric chemistry and physics, physical oceanography, hydrology, glaciology, and related sciences.
• NACA-National Advisory Committee for Aeronautics
  The UK archive of digitized NACA Reports maintained by the AERADE team.
• NTIS - National Technical Information Service
  Provides access to millions of scientific and technical reports produced by or for U.S. federal agencies.
• NTRS - NASA Technical Reports Server
  Simultaneously searches abstract and technical report servers maintained by various NASA centers and programs.
• PubList.com; The Internet Directory of Publications^SM
  A free, searchable database of over 150,000 publications.
  Indexes the journal literature of the sciences from 1940 to the present; includes cited reference search capability. The Web of Science is part of the Web of Knowledge suite of database offerings.
• Safari Technical Books Online
  Safari Tech Books Online provides access to more than 5,500 full-text e-books from O'Reilly, Sams, Peachpit Press, Que, Addison-Wesley, and other publishers. The system is distributed by ProQuest Company. Coverage includes information technology, programming, and computer applications.
• STAR - Scientific and Technical Aerospace Reports
  Abstracts for aerospace-related reports.
• Ulrich's International Periodicals Directory
  Provides bibliographic information on thousands of periodicals, including indexing information.
• Web of Science
  Indexes the journal literature of the sciences from 1940 to the present; includes cited reference search capability. The Web of Science is part of the Web of Knowledge suite of database offerings.
• WorldCat
  A bibliographic database that includes the holdings of thousands of OCLC member libraries.

Many more article search engines are available through the Harvard Libraries portal.