As a subscriber to the DWLR you have access to past Indices in our Archives section of this website. If you download the pdfs to one folder on your computer (let's call that folder "DWLR Index Archives), you can search through all of the Index pdf files at once.
First, make sure your Adobe is up to date. Then, open any one of the pdf files in the folder you've just downloaded the pdfs to. Once open you can search for a term or a phrase in just that one document or all of the pdf files in that folder. Then, click through the results until you find what you are looking for.