You can search NIPR OPAC by various fields.

DOAJ is a community-curated online directory that indexes and provides access to high quality, open access, peer-reviewed journals. You can also search open access articles via DOAJ.

The Directory of Open Access Books is a service of OAPEN (Open Access Publishing in European Networks) Foundation.

CiNii Research is a service that provides information on academic articles and research data.

【NIPR IP-range only】Scopus, provided by Elsevier, is the largest abstract and citation database of peer-reviewed literature.

Google Scholar is freely accessible web search engine for Scholarly materials.

This site provides "Earth Systems and Environmental Sciences"-focused collections of current encyclopedic and comprehensive articles.

CiNii Dissertations is a service that provides exhaustive information on Japanese Theses / Dissertations.

NDLTD Global ETD Search is a service that provides international-wide information by NDLTD (The Networked Digital Library of Theses and Dissertations).

【NIPR IP-range only】EbscoHost : Arctic and Antarctic Regions is online reference system, highly-specific "Arctic and Antarctic Regions" database.
Introductory page：Arctic & Antarctic Regions

GIS portal site provides map data of Antarctica that the Geospatial Information Authority of Japan and the National Institute of Polar Research hold were digitized for use of research or observation.

This site provides digital data of Antarctic maps (e.g. topographic map) created by the Geospatial Information Authority of Japan.

The SCAR Map Catalogue allows users to search for maps and charts of Antarctica, the Southern Ocean and subantarctic islands from over 26 countries.

This site provides the place names of Antarctica submitted by the national names committees from 22 countries.

OpenGeoSci is a free, public map based interface that allows users to search for maps, cross sections, charts, tables, figures, and data from GeoScienceWorld publications.

We provides our e-products (especially full text data) about our educational / research activity via NIPR Institutional Repository.

IRDB is a service that accumulates academic information (journal articles, theses or dissertations, departmental bulletin papers, research papers, etc.) in Japanese institutional repositories can be searched for cross-sectionally.

BASE (Bielefeld Academic Search Engine) is one of the world's most voluminous search engines especially for academic web resources. BASE provides more than 100 million documents from more than 5,000 sources.

WorldCat is the world's largest network of library content and services. WorldCat libraries are dedicated to providing access to their resources (includes their institutional repositories contents) on the web.

Internet Archive is a non-profit library of millions of free books, movies, software, music, websites, and more. Internet Archive was begun in 1996 by archiving the Internet itself.

Web Archiving Project（WARP) has been archiving websites since 2002. National Diet Library (NDL) archives public and private websites based on the NDL law or the permission of their webmasters.

DataCite is a leading global non-profit organisation that provides persistent identifiers (DOIs) for research data. To showcase and expose the metadata gathered, DataCite provides an integrated search interface.

B2FIND is a discovery service based on metadata steadily harvested from research data collections from EUDAT data centres and other repositories.
*EUDAT's vision is to enable data stewardship within and between European research communities.

PANGAEA is operated as an Open Access library aimed at archiving, publishing and distributing georeferenced data from earth system research. PANGAEA is hosted by the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI) and the Center for Marine Environmental Sciences, University of Bremen (MARUM).

NASA Open Data Portal provides NASA's datasets through the metadata or directly.