Search Engines for online journals, online references, databases, abstracts etc. :

1. BioMed Central

2. cat.inst

3. Chemical Abstracts Service

4. Directory of Open Access Journals

5. Elsevier

6. Free Medical Journals

7. Informa World

8. Medical Journals

9. PubMed

10.PubMed Central

11. Science Alert

12. ScienceDirect

13. Scientific Electronic Library Online

14. Scirus

15. SPARC

16. Wiley Interscience