1- PubMed

2- SCIRUS: Science Specific Search Engine

3-Google Scholar Search Engine

4- National Library of Medicine

5- NCBI: National Center for Biotechnology Information

6- NCBI Bookshelf(a searchable collection of biomedical eBooks)

7- MedlinePlus for background information

8- Rare Disease Information

9- National Organization for Rare Disorders( full reports are fee-based)

10- NCBI Online Mendelian Inheritance in Man database

11- American Chemical Society CASSI Tool(abbreviations for many journal titles)

12- Journal Abbreviation Resources on the Web(meta-list of tools to find journal names from abbreviations and vice versa)