Saccharomyces genome database (SGD) - http://www.yeastgenome.org/

Safari Tech Books Online - http://search.safaribooksonline.com/,
reference books for programmers and IT professionals

Safety science & risk abstracts -
http://www.csa.com/factsheets/hsrclust-set-c.php 

SBRnet - http://www.sbrnet.com/

Science citation index expanded - http://scientific.thomson.com/products/scie/

Science fiction and fantasy research database -
http://www.ala.org/ala/acrl/acrlpubs/crlnews/backissues2002/
october/sciencefiction.cfm

Science in the nineteenth-century periodical - http://www.sciper.org/

Science.gov - http://science.gov/

SciFinder Scholar - http://www.cas.org/products/sfacad/index.html

SCOLA - http://www.scola.org/eoneCommerce/Portal

Serials directory -
http://www.ebscohost.com/thisTopic.php?marketID=1&topicID=142 

Sigma-Aldrich - http://www.sigmaaldrich.com/Local/SA_Splash.html

Social sciences citation index - http://scientific.thomson.com/products/ssci/

Social sciences in forestry - http://www.eric.ed.gov/ERICWebPortal/ 

Social services abstracts - http://www.csa.com/factsheets/ssa-set-c.php

Social work abstracts - http://www.ovid.com/site/catalog/DataBase/150.jsp

Sociological abstracts - http://www.csa.com/factsheets/socioabs-set-c.php

Solid state and superconductivity abstracts -
http://www.csa.com/factsheets/solid-state-set-c.php

SORA, searchable ornithological research archive -
http://www.americanscientist.org/template/
SiteOfTheWeekTypeDetail/assetid/48264;jsessionid=baa9...

SourceOECD - http://titania.sourceoecd.org/

SPIE digital library - http://spiedl.org/

SPORTDiscus - http://www.sirc.ca/products/sportdiscus.cfm

Standard & Poor's Net advantage -
http://www.netadvantage.standardandpoors.com/

Stanford Public Information Retrieval System (SPIRES)
High Energy Physics (HEP) Database - http://www.slac.stanford.edu/spires/

STAT-USA/Internet - http://www.stat-usa.gov/

STEPsheet - http://stepsheet.stsci.edu/

Stochastic processes in physics, chemistry, and biology -
http://www.springerlink.com/content/g74w235nx267/  

Sustainability science abstracts -
http://www.csa.com/factsheets/sustain-set-c.php