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  • 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 150,000
    A and B as a phrase (directly adjoined) Quotation marklinear algebraQuotation mark 50,000
    A and/or B Left parenthesis linear algebraRight parenthesis 5 mio.
    A and B or A and C or A, B and C algebra Left parenthesis linear numericalRight parenthesis 200,000
    A or B and C or D Left parenthesis operator algorithmRight parenthesis AND Left parenthesis linear numericalRight parenthesis 1 mio.
    A and B but not C linear algebra Minusnumerical 100,000

    Please note: BASE is a search engine, not a subject database. This means that very complex search queries with nested combinations of AND, OR, parentheses or phrases are usually not possible and will lead to incorrect search results. Use phrases and parantheses only where they are absolutely necessary and split a very complex search query into single queries, if you clearly get too many or too few / no hits.

  • Word Forms, Wildcard, Synonyms

    Plural, genitive and other word forms will be searched automatically. To disable this feature, choose "Verbatim 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 synonyms and 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 (Advanced Search) Syntax (Basic Search) What happens?
    Title titColon The terms entered here will be searched in the title of a document
    Author autColon Search for authors' names. Tip: Enter only the surname of a person
    Subject Headings subjColon Relevant terms which describe the contents of a document and which have specifically been assigned to it will be searched. Note: Due to the heterogeneous distribution of content providers in BASE, the contents of this search field are also very heterogeneous, especially since the contents of this field are often not standardized. Due to this shortcoming, you may also use the Browsing for DDC to perform a subject search / restriction.
    DOI doiColon10Dotx-x-x-x/xxx Search for a DOI (Digital Object Identifier) or a group of DOIs. Enter the DOI completely or use the *, for example 10Dot1007/* or 10.1007/s13222* or 10Dot1007/s13222Hyphen017Hyphen0246Hyphen9 (always enter the DOI beginning with 10. and without https://doi.org/)
    (Part of) URL urlColon Any part of an internet address can be searched
    Publisher publColon If you search for a book or a journal the publisher's name can be searched
    Access accessColon0 1 or 2 You can limit you search for example on open access (OA) documents only (learn more about OA in our FAQ)
    Content providers contintentColoncaf cas cau ceu cna or csa
    countryColonccTLD
    collColoninternal collection name    		 You can limit your search on content providers from a particular region (continents or countries). To find documents from just one particular content provider only open the list of content providers and click on the number of documents next to name of the content provider.
    Publication Year yearColonYYYY TO YYYY
    yearColonLeft square bracket YYYY TO YYYYRight square bracket
    yearColonLeft square bracket YYYY TO *Right square bracket
    yearColonLeft square bracket * TO YYYYRight square bracket     		You can also limit your search to documents of a time period (from … to, newer than …, older than …) or using the slider in the advanced search.
    Document type doctypeColoninternal ID You can limit your search to a document type (from books to videos)
    Terms of Re-use/Licences rightsColonlicense abbrevation You can limit you search to documents with a license (see FAQ for details)
    Dewey Decimal Classification (DDC) ddcColon0* to 9*
    ddcColon00* to 99*
    ddcColon000 to 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 langColontwo-letter code You can limit the search to a language. Enter langColon in the basic search followed by the ISO 639-1 two-letter code, for example 'langColonde' for German, 'langColonen' for English or 'langColonfr' for French. We recommend to use this feature as refine option in the hitlist.

Search Result / Hit List

  • Result Display

    By default, 10 hits per page are displayed in the hit list (you can change the number of hits displayed per page in the advanced search - a maximum of 100 hits can be displayed per page). A maximum of 1,000 hits are displayed per search query, even if there are more hits for the search query. It is not possible to change this value. If necessary, use the options for refining the search result (see the corresponding section below for more information).

    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 you can find the URL of the document and the content provider from where the document was indexed.

    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.

    If the hit has a DOI, the links Citations, Cited by and More versions are displayed below the metadata.
    After clicking on the "Citations" or "Cited by" link, a check is made in Open Citations. Under "Citations", the works that have been cited in this document are displayed. If available via the Open Citations interface, the titles and authors of the works are displayed - otherwise only the DOIs. After clicking on "Cited by" the works (title or DOIs) that have cited this hit are displayed. A click on title or DOI leads you directly to the corresponding work. If the title is not listed in Open Citations, the note "No works found" appears. However, this does not mean that this title has no works cited or has not been cited.
    After clicking on the link "More versions" all titles are listed that have exactly the same DOI as the hit and that are indexed in BASE. This allows you to identify other versions that may contain additional information about the title or additional locations of the full text.

    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. There you can look up the citing articles or different "versions" of this article. Since Google Scholar sometimes performs a much more extensive citation and version analysis, you may get more results here than in the corresponding links in BASE (see above). You may not always get a result when you click on "Check in Google Scholar", 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.

  • Export hits

    You can export a single hit in different export formats via the corresponding selection box. If you want to export several hits at once, either click the checkbox next to a hit to select different hits in a hit list or click the checkbox next to "All hits" at the end of the hit list to select all hits from a hit list. Then click the "Export" drop-down menu next to "All Hits" and select an export format. You can change the number of hits per page in the advanced search. You can display a maximum of 100 hits per page and accordingly export a maximum of 100 hits at once. In total, you can display / export a maximum of 1,000 hits. If you want to export more hits, refine the search result if necessary (see the corresponding section below for more information).
    If you have installed the literature management program Zotero, you can export all records of a BASE hit list via the Zotero export icon in the address bar of the browser. Zotero is a platform-independent open-source program for collecting, managing, and citing various online and offline sources, used directly as an extension ("add-on") in the Firefox browser.

  • Sort Results

    The default sorting order is by relevance (determined for example 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 provider, 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.
    Email this search The search query can be send via a web form to an email address (you will need to login or create a personal profile to use this feature).
    Save search Save current search permanently to your search history (you will need to login or create a personal profile to use this feature).
    Browsing Find documents without typing search terms. You can choose from two kinds of browsing, by Dewey Decimal Classification (DDC) and by document type.

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
    Add a hit to the favorites
    2. Your saved favorites
    Your saved favorites
    3. Save a search
    Save a search
    4. Your saved searches
    Your saved searches