Check out the following website:
which is a clearinghouse for ALL federal jobs. Note that new jobs are continually posted on the site. Some are up for just two weeks, so one needs to be prepared accordingly. Another bit of advice is that sometimes a computer algorithm is used to "score" or match a given individual to the job qualifications — the output is a ranked list of qualified applicants. Thus, I urge you to be thorough and specific in your accomplishments. Being a government scientist is a wonderful career with tremendous potential for those of whom are ambitious, collaborate well, and work hard — with the opportunity to advance the greater good. The pay is great (especially since it is locality adjusted) and the career is stable (less anxiety over funding & tenure & teaching) with a preiminent focus on research and service.
The usajobs website does have a useful tool for keeping your job search on target. A jobs bot will send you emails when new jobs are posted that match specific keywords. I used the conjunction of several targeted keywords such as "cognitive" and "statistics" etc. to great effect.
Good luck with your job searches!