Of Course, Abode PDF reader is a excellent tool for you to find the word and Phrase in PDF files, but it is not a only tool, here is my way to use PDFXChange to achieve it in a more convenient way. You can get it with the link below:

http://www.docu-track.com/home/prod_user/PDF-XChange_Tools/pdfx_viewer/

This program has a great many of first class features which are not at all usual in freeware versions, but I am only going to concentrate on search function.

To access them go to the menu bar of PDFXChange and hover on the “search” icon button;

This gives you a fly-out menu with “Show/Hide Full Search Pane” Click on the icon and the full search pane will be opened in the display.

In the search pane you have various options. The one that interests us here is “Where would you like to search?”

If you click on the “Down arrow” at the end of the box, you get a complete navigation tree.

So, navigate to whatever directory contains the PDF files you want to search, or browse for it, and click on it to select it.

Now, any word or phrase you type into the search box will be searched for in every PDF file in that directory.  The results will be shown in the search pane. you can read the example below.

So, the results of a search for “Testing” are shown in the search pane with the title of the document as a header,and the highlighted phrase ( or word) shown as part of the text in which it occurs and a small green icon to the left of the text. If you hover on the icon with the mouse cursor it will show the page number of the document where it found the phrase.

If you click on any single result, it will be highlighted; PDFXChange opens a tab containing that document in the main view window, jumps to the page containing it, and highlights it there as well.

If you just want convert the PDF to other ducument but do not want to purchase such a expensive tool, you can employ pdf converter from Doremisoft which is also a powerful converter for converting PDF files with nice price.