Item
Item
Text
Notes
Link
RF Seek
A search engine for academic resources. More than a billion sources.World cat
search the content of 20,000 global libraries.Springer
Access to more than 10 million scientific documents: books, articles,Bioline
A library of published bioscientific journalsVolunteers
Volunteers from 102 countries collected nearly 4 million publicationsUS government for scientific sites
A U.S. government search engine for more than 2200 scientific sites.PDF books
The largest website for free download of PDF books. Claim more than 225 million titles.Academic research
One of the most powerful search engines for academic research texts. More than 100 million scientific articles, 70% of which are free