Intute*****

Excellent resource for:
Arts/Humanities
Health/Life Sciences
Science/Engineering
Social Sciences

Infomine****

Excellent resource for:
Arts/Humanities
Health/Life Sciences
Science/Engineering
Social Sciences

Labyrinth

Excellent resource for medieval studies

Techbooks for free***

FreeScience Info

free text book downloads: science, computing and engineering
Free science textbooks and software download

Google Scholar

General database for all disciplines (abstracts)

Science Direct

Abstracts for all disciplines

Protein Data Bank

Database for macromolecular structures

Pubmed*****

Medicine and Health Sciences

NCBI*****

National Centre for Biotechnology Information:
Medicine, Health Sciences, Microbiology and Biochemistry etc databases

Chemweb

Info and database for chemists and biochemists

Virtual Library****

Database for disciplines: sciences, arts, humanities. engineering, health etc

Energy Citations Database****

Physical and chemical sciences , Geography etc

Education Resources Information Centre****

Largest database on education and teaching

IDEAS: Economics database

Free database dedicated to economics and related disciplines