In cooperation with other U.S. and international institutions with archival missions, NLM endeavors to ensure permanent public access to scholarly and professional electronic works in the fields of biomedicine and health care.

When considering electronic resources for selection, the Library's intent is to apply the same criteria for scope, depth of coverage, and authoritativeness as for publications in other formats.

NLM repositories

NLM creates, or collects and makes permanently accessible, an expanding body of electronic and digital works, such as:

• journal literature deposited in PubMed Central;
• books and technical reports deposited in the Bookshelf;
• digital collections which originally were issued in print or issued as born digital and reside in the NLM Digital Collections repository; and

the Library's own electronic publishing output, including its many other publications, news items, and other works considered to be part of the NLM archives.

Access to electronic content

NLM also provides access to published electronic content. If content is licensed, the terms must allow efficient support of NLM operations, onsite services, and interlibrary loan.

An electronic resource must provide at least one of the following means of institutional access:

1. access to full text with no requirement for user registration; or

2. licensed institutional access, including IP authentication and compliance with interlibrary loan provisions and other NLM requirements.

For licensed content, NLM requires post-cancellation access, meaning continued access to all years for any subscribed content, in the event the Library cancels a title. Access may be at the publisher website, or third party trusted archive or collaborative archiving organization, as defined under the next section on preservation.

Preservation

Given the current licensing and publishing environment, and the evolution of digital preservation techniques, the Library continues to develop strategies for ensuring permanent access to content that is selected for the NLM collection and published in electronic format.

In addition to NLM managed repositories for preservation, NLM collaborates with third-party trusted organizations and repositories to preserve electronic content. A trusted repository is a library, archive, government agency, or educational institution which has made a commitment to archiving electronic resources and maintaining a reputation for technical capability and institutional stability which provides assurance that it will be able to fulfill its commitment. NLM considers repositories which have been certified by the Center for Research Libraries Certification Advisory Panel to be trusted digital repositories.

Electronic resources on physical media

NLM very selectively collects electronic works issued on physical media. Collection emphasis is on works which are valuable for research and which contain unique information, or information which is significantly enhanced by electronic presentation.

The Library selects works which exhibit good technical quality and which are produced in currently acceptable formats. NLM generally does not collect electronic media that require additional proprietary software, or software designed to be modified by the user.