Mercury's surface in "enhanced color," a color scheme created to emphasize color differences. This is not what Mercury would look like to the human eye, but by applying mathematical analysis to images, color differences can be accentuated beyond those visible to a person.
Mount Rushmore National Memorial under construction.
The workers had to endure conditions that varied from blazing hot to bitterly cold and windy. Each day they climbed 700 stairs to the top of the mountain to punch-in on the time clock. Then 3/8 inch thick steel cables lowered them over the front of the 500-foot face of the mountain in a "bosun chair." Despite the dangers, no one was killed during the project.
Otters in Glacier Bay National Park and Preserve, Alaska.
The sea otter population of Glacier Bay has increased dramatically in the past 20 years. Ecologists consider sea otters a keystone species here. Otters consume vast quantities of clams, urchins, crabs, and other invertebrates and their presence creates ripples through the ecosystem. NPS photo.
Every day someone like you becomes a wildland wildfire fighter, a teacher, a trail-builder, a museum curator, or a park ranger. Discover your opportunities in national parks. Come to play. Come to learn. Come to serve. Develop your environmental leadership skills. Find a job. Be the next generation to preserve and protect these great places.
With more than 80% of Americans living in urban areas, urban parks are more important than ever. The father of American landscape architecture, Frederick Law Olmsted, said of urban parks:
It is one great purpose of the Park to supply to the hundreds of thousands of tired workers, who have no opportunity to spend their summers in the country, a specimen of God's handiwork that shall be to them, inexpensively, what a month or two in the White Mountains or the Adirondacks is, at great cost, to those in easier circumstances.
This is a list of no-cost sources that list or index electronic texts, including journal articles or reports. At these sites you'll find electronic books, journal articles, scientific and technical reports, conference papers, fact sheets, news transcripts, preprints, theses and dissertations. Many provide the full texts online, or abstracts, while others merely list bibliographic citations.
Employees of the U.S. Department of the Interior are reminded they may also search for journal articles by using EBSCO Online, GREENR, JSTOR, or Science Direct. Most employees may search these databases at their desks, while others must come to the Library or contact a Reference Librarian for assistance.
AGRICOLA Database of citations to the agricultural literature created by the National Agricultural Library and its cooperators.
BioMed Central Publisher of more than 170 peer-reviewed open access journals.
Chemistry Central Chemistry Central is a new service publishing peer-reviewed open access research in chemistry, from BioMed Central.
Congressional Research Service Reports Congressional Research Service reports can be the best way to quickly get up to speed on major political issues. CRS is Congress’ think tank, and its reports are relied upon by policymakers and others for accurate, timely and nonpartisan analysis of important policy issues.
Digital Book Index Digital Book Index provides links to more than 141,000 full-text digital books from more than 1,800 commercial and non-commercial publishers, universities, and various private sites. More than 100,000 of these books, texts, and documents are available free.
Directory of Open Access Journals The most complete directory of open access journals, DOAJ (produced by the University of Lund Libraries) currently offers access to more than 5,000 journal titles and over 400,000 articles. It attempts to cover all subjects and includes journals that practice peer review; that do not charge readers or their institutions for access; do not use embargoes to restrict access for a period of time post-release; and, offer a majority of articles that report active research or are full-text reviews.
E-Print Network Searchable gateway to preprint servers that deal with scientific and technical disciplines
EPA Scientific Inventory The Science Inventory is a searchable database of research products primarily from EPA's Office of Research and Development.
ERIC Database Educational research reports funded by the U.S. Department of Education
GEOSCAN database GEOSCAN is the bibliographic database for scientific publications of the Earth Sciences Sector (ESS) of Natural Resources Canada
Google Scholar From one place, you can search across many disciplines and sources: peer-reviewed papers, theses, books, abstracts and articles, from academic publishers, professional societies, preprint repositories, universities and other scholarly organizations.
HathiTrust Digital Library A joint venture of more than 25 large American university libraries. More than six million volumes have been digitized and posted; about half of them are in English. About 20% of the volumes are in the public domain with full text available. Each month thousands of additional titles are added. The interface is designed much like a library's online catalog, and provides for greater precision in searching than does the Google Scholar interface. One can search by author, title, subject, and more. Filtering options include date and language, and retrieved individual titles feature a faceted sidebar suggesting similar types of works.
Health & Environmental Research Online (HERO) Health and Environmental Information Online (HERO), a continuously updated database of sources considered for and/or used in human and ecosystem risk assessments, is prepared by the Environmental Protection Agency's National Center for Environmental Assessment.
OAIster - about OAIster Search OAIster A union catalog of digital resources, OAIster provides one-stop "shopping" for users interested in useful, academically-oriented digital resources, such as digitized (i.e., scanned) books and articles, born-digital texts, audio files (e.g., wav, mp3), images (e.g., tiff, gif), movies (e.g., mp4, quicktime), and datasets (e.g., downloadable statistics files).
PolicyArchive PolicyArchive attempts to be a comprehensive, searchable, open access, online archive of public policy research. A project of Indiana University-Purdue University's Indianapolis Library and Center for Governmental Studies, PolicyArchive includes reports, briefs, charts, videos, and white papers produced by think tanks, universities, governments, foundations and public interest organizations.
PubMed Central Free online access to the full text of life science research articles
Quakeline Database Covers earthquakes, earthquake engineering, natural hazard mitigation, and related topics
Science.gov Science.gov is a gateway to authoritative selected science information provided by U.S. Government agencies, including research and development results.
SciTech Connect Science, technology, and engineering research information from the U.S. Department of Energy
SORA: Searchable Ornithological Research Archive An open access electronic journal archive and is the product of a collaboration between the American Ornithologists Union, the Cooper Ornithological Society, the Association of Field Ornithologists, the Wilson Ornithological Society and the University of New Mexico.