1.   Journal Citation Reports  (Impact Factor Checker) 

URL  : Journal Citation Reports

          Journal Citation Reports® is a comprehensive and uinque reouce that allows your to evaluate and compare journals using citation data drawn from over 7,500 scholarly and technical journals from more than 3,300 publishers in over 60 countries. It is the only source of citation data on journals, and includes virtually all areas of science, technology, and social sciences Journal Citation Reports can show you the:

         *  Most frequently cited journals in a field
         *  Highest impact journals in a field
         *  Largest journals in a field 

  User's Guide :  Journal Citation Reports