[support] sql query and other

[Simone Dal Maso]

Hi,
I have a big problem.
I have a ejournal in my website and I have about 1000 articles.
Unfortunately, some of these are token from a website that has changed its 
policy and don't allow us to publish its material: only the 25% of articles 
can be published.
We can distinguish these articles because there is always the original link 
that obviously starts with the same strings.
We must select all the articles containing these strings in their body, and 
tells drupal to take the first 4 5 lines and delete the rest of contents.
I have 2 ideas, but I' not able to make it:
1. with a sql query, I think all contents are in the node_revisions table.
2. publishing only the teaser of the article.
I think the second method is easier, but have you got some ideas how publish 
only a teaser and hide the entire body of some nodes?

thanks for your attention and patience.
Bye.