which language to index an article archive?

I have a bunch of newspaper articles that I'd like to put online as a searchable archive. The only search parameter I think I'll need (in addition to full text) is a category field that is populated by myself. That is, people can search the database for certain words or phrases that exist within the article text; or, they can choose from a set list of topics and are given every article that fits that topic. I determine which topics are appropriate for each article, and an article can have more than one topic. What type of database should I use for this? I have experience only with PHP, but I'm eager to explore other ways of doing this.

thanks,
Matt