The journal impact factor is a measure of the frequency with which the "average article" in a journal has been cited in a particular year. It is calculated by dividing the number of current citations to articles published in the two previous years by the total number of articles published in the two previous years. The impact factor will help you evaluate a journal’s relative importance, especially when you compare it to others in the same field.
A priority of the NIH Library is to provide seamless access (by IP recognition) to all electronic resources. However, because some publishers are not yet offering the access through IP recognition we do have to accept password dependent access. When a password is needed for an NIH user (NIH staff) it appears in the "Notes" column of the table display for online journals.
Non-NIH users will not see information in that column as publisher licenses restrict us to offering electronic resources to NIH staff only.
The journals of the Neuroscience Center and the NIAID Rockledge libraries were purchased by their respective institutes for the use of their own staff. They may not be borrowed nor do they offer photocopy services. Submit a document request to the NIH Library for any journal article needed.