想了解一下，可是每个地方都要输入代码查询，我都不知道有哪些公司，那些公司的情况如何，怎么个查法啊？

有没有地方列出来所有的纳市上市公司都有哪些的？

Here is the link that you can find such information: http://research.investopedia.com/stocks/nasdaq_quotes.aspx.

However, if want to see their financials or annual reports online, you have to log into some paid sites to view it, such as, Bloomberg, EDGAR, etc.

It's impossible for an invidual to check all companies information. even you have the access, you won't have the time to analysis all of them.

focus on a sector you like/familiar.