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Search engines basically support additional logical command queries, often with "+" and "-" numbers, or Boolean (Boolean) logical commands and, or, and not. Using these command symbols can greatly improve our search accuracy. Compare the meanings of the following search terms:
Computer adventure game
The most basic way to search. Looking for records related to the keyword, which in the past normally corresponds to the "OR" in Boolean logic commands, translates to:
Computer (or) adventure (or) games
Therefore, there are not only records with three keywords in the search results, but also records that contain only a subset of key strings (such as computer games) and individual keywords such as computer. The current trend of search engines is to match all keyword searches by default, that is, to return only the records containing all the keywords, which is equivalent to the "+" number and the relationship between and and, of course, sometimes exceptions.
+computer +adventure +game
Equivalent to the "and" Relationship in Boolean logic commands, translation is:
Computer (and) adventure games
Therefore, only records containing three keywords are listed in the search results. Using the "+" number in search conditions can also force search engines to search for keywords as keyword. For example, when we search for "Who am I", where the "who" and "I" are deactivated words, we can add "+" before two words to force it to search, at this time the search conditions can be: +who +am +i.
+computer +game-adventure
Translation is:
Computer (and) game (not) adventure
Lists all records that contain computer game, but excludes records about adventure.
To sum up, the "+" number (and) is used to specify that an item is covered in the search, and the "-" sign (not) is used to exclude an item from the result.