| NEI | National Eye Institute |
|---|---|
| NIA | National Institute on Aging; nephelometric inhibition assay; niacin; no information available; Nutri... |
| INRIA | National Institute for Research in Computers and Automation [France] [Institut National de la Recher... |
| NII | National Information Infrastructure; National Insurance Institute |
| NCA | National Certification Agency; National Council on Aging; National Council on Alcoholism; neurocircu... |