Where can I find a database of publicly-owned, listed stocks (either
online or downloadable)that I can query (preferably free) to find a
list of companies that fit certain criteria for p/e ratios, working
capital, price, etc.?

Hello,

Yahoo has a free stock screener that will do much of what you want.
http://screen.yahoo.com/stocks.html

You can sort all listed public stocks by Industry, index, share price,
average share volume, market cap, dividend yield, performance, sales
revenue, profit margin, price/earnings ratio, price/book ratio,
price/sales ratio, PEG ratio, estimated growth.

If that doesn’t screen for everything you are interested in, Yahoo &
Smart Money also have an offer for a paid stock screener that is even
more powerful.  It has a two week free trial.
http://www.smartmoney.com/yahoo/yahoo.html


There are other stock screeners on line as well.  You can try them all
and decide which is better for your needs.  Most have a membership
fee.  But, most also, have a fee trial period.  Here are a few that I
found.

Stockworm
http://www.stockworm.com/tours/stock-screener.html?coupon=google_s1

Quicken
http://www.quicken.com/investments/stocks/search/full/

MarketScreen
http://www.marketscreen.com/

Hoover’s Online
http://www.hoovers.com/search/forms/stockscreener/0,2221,71,00.html

StockSelector.com
http://www.stockselector.com/screen.asp


The next site is one which has evaluated many stock screens on the
web.  It has links to ones it has evaluated, as well as links to ones
it has not.  You should be able to find something to fit your needs
here.

Foster Business Library
http://depts.washington.edu/balib/stocksites/


Keywords Used: 
I have used the yahoo screen before.  So, I knew they were there. 
But, you can go to www.yahoo.com and click on “business & economy”. 
Then “finance & investment”.  Then “Yahoo! Finance”, “stock research”
and “stock screener”.  Although, this last page where you click on
“stock screener” has other research engines that might be useful for
you.

"stock research screen"
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=stock+research+screen&btnG=Google+Search

http://search.dogpile.com/texis/search?q=stock%20research%20screen&geo=no&fs=web&top=1

I hope this helps.
pba

I'm a little embarrassed that I didn't find for myself some of the
references listed in the answer; however, the resources gained are far
beyond anything I expected. I can essentially shape any part of my
stock portfolio with a myriad of both technical and fundamental
attributes. Thanks so much.