BASE - Bielefeld Academic Search Engine



  • General Information

    In BASE two different search surfaces are available: a basic search providing a single search field (search in all parts of a document by default) and an advanced search with multiple search fields and more sophisticated search options. In the basic search you get search suggestions after typing at least 3 letters. By selecting a search suggestion you can apply it to the search field.

    You can search the metadata of all indexed documents. Due to time and performance constraints we are indexing only metadata of documents. Thus it's not possible to search the full text of the indexed documents. You should start with a general search and enter 2-3 search terms. BASE provides several options to improve and refine the retrieved search result. About 60% of the indexed documents in BASE are open access, the rest are mere metadata entries without full text or are not freely accessible.

  • Combining Search Terms

    Entering one or more search terms (separated by blanks) will produce hits, which include all the entered terms in one document (and conjunction). There are, however, more options to combine terms and to search efficiently.

    You search ... Example Hits (ca.)
    A and B linear algebra 95,000
    A and B as a phrase (directly adjoined) "linear algebra" 35,000
    A and/or B (linear algebra) 2,500,000
    A and B or A and C or A, B and C algebra (linear numerical) 120,000
    A or B and C or D (operator algorithm) AND (linear numerical) 800,000
    A and B but not C linear algebra -numerical 75,000
  • Word Forms, Wildcard, Synonyms

    Plural, genitive and other word forms will be searched automatically. To disable this feature, choose "Exact search" in the advanced search or in the search field on the hitlist.

    If you choose the option "Multi-lingual search" in the advanced search or in the search field on the hitlist you can also search for translations, provided that the search term is included in Eurovoc Thesaurus or Agrovoc Thesaurus. Example search for climatology.

    The * (asterisk) substitutes any number of characters. It is used to find different spellings or wordings even in different languages in one go. Example: algebr* geometr*. If you use asterisks, the automatic search for word forms or synonyms will be disabled. The asterisk can not be applied in phrase searches.

  • Limit Search Area (Search Fields)

    To limit the search area you can use several search fields in the advanced search or the appropriate search syntax in the basic search.

    Search Field (Adv. Search) Syntax (Basic Search) What happens?
    Title tit: The terms entered here will be searched in the title of a document
    Author aut: Search for authors' names. Tip: Enter only the surname of a person
    Subject Headings subj: Relevant terms which describe the contents of a document and which have specifically been assigned to it will be searched. Tip: You may also use the browsing option
    DOI doi:10.[xxxx/xxx] Search for a DOI (Digital Object Identifier) or a group of DOIs. Enter the DOI completely or use the *, e.g. 10.1007/* or 10.1007/s13222* or 10.1007/s13222-017-0246-9 (always enter the DOI beginning with 10. and without
    (Part of) URL url: Any part of an internet address can be searched
    Publisher publ: If you search for a book or a journal the publisher's name can be searched
    Access access:[0 1 2] You can limit you search e.g. on open access (OA) documents only (learn more about OA in our FAQ)
    Content sources contintent:[caf cas cau ceu cna csa]
    coll:[internal collection name]
    You can limit your search on content sources from a particular region (continents or countries). To find documents from just one particular content source only open the list of content sources and click on the number of documents next to name of the source.
    Publication Year year:[YYYY]
    year:[YYYY TO YYYY]
    year:[YYYY TO *]
    year:[* TO YYYY]
    You can also limit your search to documents of a particular publication year or a time period (from … to, newer than …, older than …) or using the slider in the advanced search.
    Document type doctype:[internal ID] You can limit your search to a document type (from books to videos)
    Terms of Re-use/Licences rights:[license abbrevation] You can limit you search to documents with a license (see FAQ for details)
    DDC ddc:[000-999] You can limit the search to one or several classification codes from the DDC (Dewey Decimal Classification). If you do not know the DDC number you can use the Browsing by DDC or use the refine option in the hitlist.
    Language lang:[two-letter code] You can limit the search to a language. Enter lang: in the basic search followed by the ISO 639-1 two-letter code, e.g. 'lang:de' for German, 'lang:en' for English or 'lang:fr' for French. We recommend to use this feature as refine option in the hitlist.

Search Result / Hit List

  • Result Display

    In the result list 10 hits per page are shown by default (you can change the number of hits shown per page in the advanced search).

    The hits are consecutively numbered. Next to the number of a hit, you can find the title. Clicking on the line will open the URL which appears below. You can access the full texts of about 60% of the indexed documents (Open Access), the rest are mere metadata entries without full text or are not freely accessible. Documents which are clearly marked as Open Access by the content providers are indicated with an icon Open Access. Due to the fact that many content providers do not provide sufficient information wether a document is open access or not, we can display the icon at about 25% of all documents only.

    In case this document contains metadata they will be displayed below the title, highlighted in light green. If there are no metadata assigned to this document, a teaser from the document will appear instead. Below the highlighted paragraph there are URL of the document and content provider. Content provider means the source from which the document originates.

    Next to each author name you will find the link claim. If you are the author of this publication you can claim this publication and connect it to your ORCID iD. You can also push the metadata of this publication (author, title, publication year etc.) directly to your list of works at ORCID. Please use this feature only if you are author of this publication. We regularly check all links from BASE to ORCID iDs. Incorrect links will be deleted in BASE and from your publication list in ORCID when indicated.

    At the bottom of a hit, the link Check in Google Scholar will appear. When clicking this link, a search for this particular title will be performed in Google Scholar and the result of this search will be displayed in a new browser window (note example below). There you can look up the citing articles or different "versions" of this article. You may not always get a result, because BASE indexes sources more thoroughly than Google Scholar does. Or, some of the resources indexed in BASE are not available in Google Scholar.

    Next to the link to Google Scholar you can email this hit or export the record to a reference management software.

  • Sorting Results

    The default sorting order is by relevance (determined e.g. by occurence of the search term in the title or in the metadata). Next to the search results on the right a "Sort your Results" box is provided where you can individually select from three sorting aspects and determine the order. Documents without an author or publication date will appear first or last, depending on your choice of order.

  • Refine Search Result

    On the right hand side of the search result page, several options to refine the search result are displayed. You can individually select and refine your search result by author, subject, DDC (classification), year of publication, content source, language and document type. The provided options for refining depend on the search results. If, for example, all hits are in English, the option "language" will not be offered.

  • Remove Filters

    If you have refined your search result, you can remove these refinements here.

  • More Options

    Some more options are displayed in this box:

    Option Hint
    Search History In the search history the last ten search requests are displayed, along with the number of retrieved hits. Each of the entries can be reactivated by clicking the respective link. The search history will be deleted as soon as the browser window is closed.
    Get RSS Feed You can subscribe an RSS Feed for each query. You will be informed via RSS of the availability of new resources according to the keywords and search parameters you specified.
    Email this search The search query can be send via a web form to an email address.
    Browsing Find documents without typing search terms. You can choose from two kinds of browsing, by Dewey Decimal Classification (DDC) and by document type.
    Search Plugin With our search plugin you can search the academic web with BASE directly through the search toolbar of your browser.

Personal Login

  • General Information

    In BASE you can create a personal profile and claim the authorship of a publication (see our FAQ for more information), add favorites and save your search history permanently

  • Demonstration of some features (click on image to magnify):
    1. Add a hit to the favorites
    2. Your saved favorites
    3. Save a search
    4. Your saved searches