As discussed on this blog in the past, the Windows command findstr can be used to perform complicated searches through multiple files, including regular expression searches.   Here's a quick demo of how findstr can be used to search for multiple search terms in multiple files.

Compose a batch file with this code:

@echo off

for /F %%i in (searchlist.txt) do (
echo Files containing %%i
findstr /C:%%i /S *.txt
)

[Enter this in a text file and then save it with the extension 'bat'. ]

'searchlist.txt' refers to a file listing the strings you want to search for.  Each string needs to be on a separate line. 

The end of the code [*.txt] specifies that only .txt files should be searched. 

The result shows the hits in context for each file, one search term at a time:

Files containing court
frankenstein.txt:courtyard belonging to the house which I inhabited, where I remaine
frankenstein.txt:of the court, which had that night been my asylum, and I issued int
frankenstein.txt:as witnesses, I accompanied them to the court.  During the whole of
frankenstein.txt:court she threw her eyes round it and quickly discovered where we w
frankenstein.txt:his neck, a murmur of horror and indignation filled the court.
frankenstein.txt:the court.
frankenstein.txt:I rushed out of the court in agony.  The tortures of the accused di
frankenstein.txt:the court; my lips and throat were parched.  I dared not ask the fa
frankenstein.txt:court.  He made, at that moment, a solemn vow to deliver him and th
frankenstein.txt:town where the court was held.  Mr. Kirwin charged himself with eve
frankenstein.txt:brought before the court that decides on life and death.  The grand
mobydick.txt:sanctity, that I could not suspect him of courting notoriety by any
mobydick.txt:to him who, in this world, courts not dishonor! Woe to him who would
mobydick.txt:has proved but hollow courtesy. I drew my bench near him, and made some
mobydick.txt:Babylon; and to have been Belshazzar, not haughtily but courteously,
mobydick.txt:the shipΓÇÖs cabin belongs to them; and that it is by courtesy alone th  

. . . and so on. 

Thanks to Srini for the code.