The result count in the header of the search result is the total for all namespaces; accordingly there are links to supposed other pages with results; correctly a lower number of results is actually presented. (bugzilla:2895)
Search facilities in MediaWiki
This page explains the search button for the search box which appears on every page,
and the "Search result settings" section in the preferences.
Pressing the [Enter] key while the search field is active is equivalent to clicking on the [Go] button. While this is obvious when using Internet Explorer (tested on version 6), Mozilla (version 1.6 at least) provides no such indication.
Avoid short and common words
This is the most likely cause of an unexpected failed search.
If your search terms include a common "stop word" (such as "the", "one", "your", "more", "right", "while", "when", "who", "which",
"such", "every", "about", "onto"), then your search will fail without any
results. Short numbers, and words that appear in half of all pages, will also not be found.
In this case, drop those words and rerun the search.
See Help:Common words, searching for which is not possible for the stop words filtered out by the database. From there one can at least go to a page with a stop word as title. Searching for the combination of one or more words and the common word "not" give a database query syntax error due to a bug in the software.
The searches for "fortran", "Fortran" and "FORTRAN" all return the same results.
Words with special characters
In a search for a word with a diaeresis, such as Sint Odiliënberg, it depends whether this ë is stored as one character or as "ë". In the first case one can simply search for Odilienberg (or Odiliënberg); in the second case it can only be found by searching for Odili, euml and/or nberg. This is actually a bug that should be fixed -- the entities should be folded into their raw character equivalents so all searches on them are equivalent. See also Help:Special characters.
There is no method for searching for a phrase. Contrary to what you might expect, enclosing phrases in double quotation marks such as "can of tuna" will retrieve all pages containing "of" "tuna" and "can".
Searching limitations and Gotchas
No regular expressions or wildcards
You cannot use regular expressions or wildcards such as ? or *. If you don't know what that is, don't worry about it. To search for pages with the words "boat" or "boats" search like this: "boat or boats".
Words in single quotes
If a word appears in a page with single quotes, you can only find it if you search for the word with quotes. Since this is rarely desirable it is better to use double quotes in pages, for which this problem does not arise.
An apostrophe is identical to a single quote, therefore Mu'ammar can be found searching for exactly that (and not otherwise). A word with apostrophe s is an exception in that it can be found also searching for the word without the apostrophe and the s.
Delay in updating the search index
For reasons of efficiency and priority, very recent changes to pages are not always immediately taken into account in searches.
The search only applies to the namespaces selected in the preferences. To search the other namespaces check or uncheck the tickboxes in "Search in namespaces" box found at the bottom of a search results page. Depending on the browser, a box may still be checked from a previous search, but may no longer be effective. To be sure the box is in effect, uncheck and recheck it.
Searching the image namespace means searching the image descriptions, i.e. the first parts of the image pages. For searching the titles, use Special:Imagelist.
The number of search results reported seems to be the total for all namespaces; accordingly there are links to supposed other pages with results; correctly a lower number of results is actually presented.
(Also there is a special search feature Special:Imagelist, which searches in titles, regardless of whether there is an image description.)
Some portions of matching pages that contain the searched-for terms are shown, with the terms highlighted in red. You can set the number of lines extracted and the amount of text per line shown in your preferences.
If you search e.g. for "book" you get only pages with that word, not pages with "books" only. However, on pages with "book" and "books", also the part "book" of the word "books" is highlighted.
This page is a copy of the master help page at Meta (for general help information all Wikimedia projects can use), with two Wikipedia-specific templates inserted. To update the main text, edit the master help page for all projects at m:Help:Searching. For Wikipedia-specific issues, use Template:Ph:Searching (the extra text at the bottom of this page) or Template:Phh:Searching for a Wikipedia-specific lead (text appears at the top of this page). You are welcome to copy the exact wikitext from the master page at Meta and paste it into this page at any time. To view this page in other languages see the master page at Meta.
To search any Wikia wiki, you can use the search bar above the sidebar on the right.
Your initial search will probably only search the main namespace and a few others. After you search, you may find that you need to expand your search to other areas of the wiki. To do this, click the "Advanced" link that appears at the bottom of your search results. It will open a box that allows you to select more namespaces and continue searching.
Other ways to find pages
To search for wikis across Wikia, use the search box on our main page.