Often institutions have subscriptions to journals and can give you access to the PDF files. Further, many journals open their material to the public after a certain period of time. Thus, it makes sense to try to get a hold of the papers electronically. Sometimes it also helps to contact the authors directly. And most are happy to hear that someone out there reads their stuff.
- Index based Database with abstract and full-text
- PubMed(free): a powerful database in the area of the life sciences http://www.ncbi.nlm.nih.gov/pubmed/
- Google Scholar http://scholar.google.com/ is a freely-accessible Web search engine that indexes the full text of scholarly literature across an array of publishing formats and disciplines.
- ISI Web of Science(by institution subscription) is an online academic database provided by Thomson Scientific's Institute for Scientific Information http://thomsonreuters.com/products_services/science/science_products/a-z/web_of_science
- ScienceDirect http://www.sciencedirect.com/ is one of the largest online collections of published scientific research in the world. Produced by Elsevier, it contains over 9.6 million articles from over 2500 journals, over 6,000 e-books, reference works, book series and handbooks. (by institution subscription)
- Scopus http://www.scopus.com/ is the largest abstract and citation database. It covers over 16,500 titles from more than 4,000 international publishers, including coverage of 37 million records, of which: 18 million records include references going back to 1996 (75% include references) 19 million pre-1996 records go back as far as 1823. (by institution subscription)
- EBSCO http://search.ebscohost.com/ - Provider of EBSCOhost®, the leading search platform for full-text online research databases in institutions worldwide. (by institution subscription)
- HighWire Press http://highwire.stanford.edu is the largest archive of free full-text science on Earth! As of 7/8/09, we are assisting in the online publication of 1,918,831 free full-text articles and 6,062,314 total articles. There are 8 sites with free trial periods, and 47 completely free sites. 282 sites have free back issues, and 1181 sites have pay per view!
- JSTOR (short for Journal Storage) http://www.jstor.org is a United States-based online system for archiving academic journals, founded in 1995. It provides full-text searches of digitized back issues of several hundred well-known journals, dating back to 1665 in the case of the Philosophical Transactions.