Aaron Axelsen

The Advanced Search Widget is designed to be a replacement to the defaut search widget. The Advanced Search Widget allows you to search for only a 
specific post type and also select which fields to query (title, content, tags).
In addition, it is also possible to place multiple widgets onto the sidebar to search through different custom post types.

Advanced Search Widget

Allows you to add a widget to search custom post types along with other options

bestweblayout

Ono Oogami

WordPress has a build-in search system which actually allows searching posts in certain one or mutiple category(s), month archive(s) and tag(s). However, by default you must manually add extra GET/ POST parameter to search query to enable these features.
This plugin enhanced the wordpress search form so visitors can submit a more advanced search query via XHTML visual Form, allowing setting conditions that posts should be in some category(s), publish in which month, having some tag(s) and other conditions. Mutiple conditions are allowed and connected by AND Boolean operation.
Go to “Installation” tab to see how to install and use this plugin. Goto “Screenshots” tab to see what enhanced search form likes.
<h4>Translation</h4>
<ul>
<li>Russian (ru_RU)</li>
</ul>

Enhanced Search Form

Enhance wordpress search form to allow searching posts in certain category(s), month archive(s) or tag(s).

Advanced Search Widget vs Enhanced Search Form