You can use Adobe Reader to find text in multiple PDFs:
The Search window enables you to look for search terms in multiple
PDFs. For example, you can search across all PDFs in a specific
location or all files in an open PDF Portfolio.
- Open Acrobat on your desktop (not in a web browser).
- Do one of the following.
- In the Find toolbar, type the search text, and then choose Open Full Acrobat Search from the pop-up menu.
- In the Search window, type the search text.
- Shift + Ctrl + F
- In the Search window, select All PDF Documents In. From the pop-up menu directly below this option, choose Browse For Location.
- Select the location, either on your computer or on a network, and click OK.
- To specify additional search criteria, click Show Advanced Options, and specify the options.
- Click Search.
Note: If documents are encrypted (have security applied to them), you
cannot search them as part of a multiple-document search. Open those
documents first and search them one at a time. However, documents
encrypted as Adobe Digital Editions are an exception and can be
searched as part of a multiple-document search.
During a search, you can click a result or use keyboard shortcuts to
navigate the results without interrupting the search. Clicking the
Stop button under the search-progress bar cancels further searching
and limits the results to the occurrences already found. It doesn’t
close the Search window or delete the Results list. To see more
results, run a new search.