This page explains how to search the wiki for what you are looking for.
Avoid short and common wordsEdit
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.
Search is case-insensitiveEdit
The searches for "addtv", "Addtv" and "ADDTV" all return the same results.
Boolean search possibleEdit
You can use the words "and", "or" and "not" and parentheses in order to formulate more complicated requests. If none of those words is specified, "and" is used by default. For instance, "Seth not Green" will return all pages that contain the word "Seth" but don't contain the word "Green". The search "(Green or MacFarlane) and Seth" will return all pages which contain "Seth" and either "Green" or "MacFarlane".
To search for a phrase, enclose it in double quotation marks.
Searching limitations and GotchasEdit
No regular expressions or wildcardsEdit
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 quotesEdit
If a word appears in an 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 indexEdit
For reasons of efficiency and priority, very recent changes to pages are not always immediately taken into account in searches.
Search Options Edit
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 without being effective any longer! To make sure, uncheck and recheck it.
Searching the image namespace means searching the image descriptions, i.e. the first parts of the image description pages, and the titles, but only of those images which have an image description!
(Also there is a special search feature Special:Imagelist, which searches in titles, regardless of whether there is an image description.)
Redirects can be excludedEdit
Check or uncheck the tickbox "List redirects" in "Search in namespaces" box found at the bottom of a search results page.
The wikitext is searchedEdit
The wikitext (source text, what one sees in the edit box) is searched. This distinction is relevant for piped links, for Interwiki links, special characters (if ê is coded as ê it is found searching for ecirc), etc.
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.
(Some content taken from meta.wikimedia.org)