- which files do you have?
- which version of Oracle database did they belong to?
- how were they backed up?
- what kind of data would you like to read? (text or also numeric/date formats?)
- what do you already know about the data you are looking for?
- how did you get these files in your possession?
- what volume of data do you expect to have to read/recover?
If the files happen to be from a valid backup you could have some luck, but mostly because you could turn in into a running database again. The complete system tablespace should be among the files you have to make a chance.
Only reading data from the bare dbf files .... there are many options that make this hard to do. Depending on what you know about what you are looking for makes this more or less possible. Start with: forget it and be happy with any word you can recover this way.
dd and od might be your friends, compression and encryption not.
Maybe Kurt can help you, see dude could be your best option.