Search using a keyword
This is the most basic search method. Simply specify a keyword to search for.
eg. accident

Search using AND
This search method allows you to search for a sentence that includes two keywords. It is an effective method to narrow down the search results. You may also designate 3 words or more. Insert "and" between the words.
eg : accident and prevention

The "and" may be omitted. When you space out and rank a word with another, the search automatically takes place using the AND method.

Search using OR
This search method allows you to search for a sentence that includes any of the entered keywords. You may also designate 3 keywords or more by inserting "or" between the words.
eg. : collapse or falling

Search using NOT
This search method allows you to search for a sentence that includes one keyword, but excludes another certain keyword. You may also designate 3 keywords or more by inserting "not" between the words.
eg. : explosion not fire

Grouping
It is possible to group combinations of AND, OR, and NOT searches, using parenthesis. A space must be left between the parenthesis and the keywords.
eg. : ( explosion or fire ) and accident

Search by phrase
You can search for a particular phrase by bracketing the phrase with double quotation marks or brace marks. The phrase search engine is not 100% accurate.
eg. : {chemical safety}

Search for a partial match
A partial match search can be categorized into three types; the front match search, the middle match search and the rear match search.

The front match search

inter* (Searches for words starting with "inter".)

The middle match search

*safe* (Searches for words containing "safe".)

The rear match search

*net (Searches for words ending with "net".)

The regular expression search
Designate a keyword to be searched in a regular expression search. The regular expression is surrounded by slashes /.../. Ruby code is used in the engine of the regular expression search. The regular expression format is approximately the same as in Perl.
eg. /pro(gram|blem)s?/

Field Designation Search
This is a search method designating a field, for example: Subject:, From:,Message-Id:. Particularly, it is effective when dealing with Mail/News files.

eg. :

• +subject:Linux
  This refers to a sentence in which Linux is included in the Subject.
• +subject:"GNU Emacs"
  This refers to a sentence where GNU Emacs is included in the Subject field.
• +from:foo@bar.jp
  This refers to a sentence where foo@bar.jp is included in the From field.
• +message-id:<199801240555.OAA18737@foo.bar.jp>
  (This refers to a search for a specific Message-Id.)

Special Notes

• You do not have to differentiate between a capital letter and a lower case letter in any of the above retrieval methods.
• You can divide a compound Japanese word into morpheme unit and then search it by phrase. Beware of dividing a word inappropriately.
• Double-byte numbers and special characters will be treated as their single-byte counterparts.
• You can search a word with denotation. eg.: TCP and IP. However, because the treatment of the denotation is imprecise, it is advised that you search using AND to divide the phrase. This results in better hit rates. (It may result in too many hits instead).
• It takes a little more time to search by the middle search, rear search, regular expression and field designation.
• When you want to search a word with AND, OR, or NOT, you bracket the word, using double quotation marks or braces.