NIH Guide - An excellent source for information their current programs, funding targets and changes in policy and administration. They have a searchable database that you can explore using keywords and phrases, or by date. You can also subscribe to their weekly content notification via email using their NIH Guide Table of Contents Notification LISTSERV service, and then using the embedded URLs to access Guide Article.
Federal Register - The official daily publication for Rules, Proposed Rules, and Notices of Federal agencies and organizations. It can be searched by field, date, agency, citation number, volume and page number, or subject (keyword).
Grants.gov - Good source to find and apply for federal grants.
COS - COS is the leading global resource for hard-to-find information critical to scientific research and other projects across all disciplines. Find funding with COS Funding Opportunities by searching a comprehensive funding resource, with more than 25,000 records worth over $33 billion. Identify experts and collaborators with COS Expertise by searching among 500,000 profiles of researchers from 1,600 institutions throughout the world. Discover who’s doing what — current research activity, funding received, publications, patents, new positions and more.