| The following characters have a special meaning. Put them next to a word without a space between. |
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| " " | encloses a sequence of words so that the sequence is searched as a whole. |
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| + | The following word must appear. |
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| - | The following word must not appear. |
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| ~ | The following word should not appear but may appear. |
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| < | The following word should appear but is not as relevant as other words. |
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| > | The following word should appear and is more relevant than other words. |
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| ( ) | groups words together so that one of the prefixes above can be applied to the whole group. |
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| * | is a wildcard behind a word, representing null, one or several arbitrary characters. |
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