With HPB you can modify your query in such a way that you search for a specific subject, publication or author. Using Boolean, wildcard and proximity operators you can modify a general query so that the search more closely approximates your expectations.

In addition to search using standard search operators, it is possible to use parentheses in a query to nest search operators. Complex search operators are possible thanks to the ability to combine multiple search operators, while fill words are ignored during the search.

Descriptions of the search keys available from the drop-down menus can be found on Simple Search page. An extensive documentation of all available search keys is available on this separate help page.

Search using search operators

HPB supports the following search operators: Boolean operators,  Proximity operators, Wildcards and Reserved words.

Boolean operators

If your search query is too generalised you may receive an unmanageable number of hits, or too few if the search term is too specific. To achieve better results, you can use Boolean operators in your search.

Proximity operators

You can use proximity operators to specify whether the phrase you are looking for should be searched in the specified word order or with terms in between.

Wildcards

You can use wildcards when you are not sure how to spell a search term or you also want to search for similar terms in the same search. Wildcards can be placed at the end or in the middle of a term, but never at the beginning.

Reserved words

All the operators used in searches are reserved words. The system understands operators entered in both German and English:

and – or – not – near
und – oder – nicht – bei

Problems arise when you run a search using search terms that match one of these operators. If possible, you should omit these terms altogether or enclose them in quotation marks or “neutralise” using a backslash.

For example, if you are searching for a title with the keywords “Money” or “Life”, the system interprets this as a search for the term “Money”OR the term “Life” and returns titles that contain one or the other term. Or if you try searching for the title “Not Fish not meat”,  the system understands the word NOT as an operator and searches for titles that contain neither one nor the other term – which in this case provokes an error message.

However, if you do want to use expressions that contain the reserved words, then you must either enclose them in quotation marks or neutralise them with a backslash, e.g.

Money “or” life
money \or life
fish “not” meat
fish \not meat

Parentheses: nesting multiple search operations

You can also use parentheses in a query. Without parentheses, a query is performed according to the hierarchy of the search operators. That is, the operator that is highest in the hierarchy takes precedence. Proximity operators have the highest position in the hierarchy, followed by AND and then OR. Parentheses ensure that this hierachy is ignored. This enables you to nest your search operations.

For example: (“auto” OR “bicycle”) AND (“transport” OR “highway”) finds titles that contain “auto”and/or “bicycle” and that also include “transport” and/or “highway”.

Combining search operators: examples of complex search operations

It is possible to compose complex queries by combining search operators such as Boolean, wildcards and proximity operators.

  • Example 1: complex query
    “NOT johann ? bach” searches for titles that contain the word bach not preceded by the word johann. This search operation will not find a title containing “johann sebastian bach”, because in this title johann precedes bach. This search operation will find the title wilhelm bach, johann bach because the title contains an occurrence of bach not preceded by johann.
  • Example 2: complex query
    “Einstein ##! gravity” searches for titles that contain einstein and gravity with three or less intervening words. The query “einstein NEAR/3 gravity” searches for titles that contain “einstein” and “gravity” (or “gravity” and “einstein”) with three or less intervening words.
  • Example 3: complex query
    “Einstein ### gravity” finds titles that contain einstein and gravity with four or less intervening words. Another possibility for finding the same result is: “einstein #/4 gravity”

Articles, prepositions and other fill words

Every word in a title is indexed with the exception of fill words. Fill words are words that are ignored during a search to prevent irrelevant information from being displayed. Articles, pronouns, adjectives, adverbs and prepositions are examples of fill words. Words that appear, but have no relevance during a search. For example: “the”, “him”, “a”, “of”, “in”, etc.