I'm very happy to learn. I have not taken what parv said before badly. I know the title was wrong and I understand the reason, because I've spent a lot of time serching archives of this site for coming up with a solution to my problem.
I've serached a lot and found this: How do I extract all text between two keywords like start and end? which is exactly what I need to do. The only problem is: I need to extract only sentences that have just three or four word between said keywords, and not match the other.
Let's say that my keywords are atomo and nucleo. I'd like to extract just this:
atomo/atomo/S-MS  Ë/essereV-S3IP  composto/comporre/V-MSPR  da/da/E  un/un/RIMS  nucleo/nucleo/S
but not this:
 atomo/atomo/S-MS  non/non/B  era/essereV-S3II  indivisibile/indivisibile/A-NS  ,/,/PU  bensÏ/bensÏ/C  a/a/E  sua/suo/A-FS  volta/volta/S-FS  composto/comporre/V-MSPR  da/da/E  particelle/particella/S-FP  pi˘/pi˘/B  piccole/piccolo/A-FP  (/(/PU  alle/a/E-FP  quali/quale/P-NP  ci/ci/PQNP  si/si/PQNN  riferisce/riferireV-S3IP  con/con/E  il/il/RDMS  termine/termine/S-MS  "/"/PU  subatomiche/subatomico/A-FP  "/"/PU  )/)/PU  ././PU  In/in/E  particolare/particolare/S-MS  ,/,/PU  l'/lo/RDNS /atomo/atomo/S-MS  Ë/essereV-S3IP  composto/comporre/V-MSPR  da/da/E  un/un/RIMS  nucleo/nucleo/S.
I managed (more or less) to do what is suggested in the link I posted before, but I don't know how to tell the regex that I don't want every single sentence that start with a keyword and end with the other, but just sentences that have three or four words between the first and the second.
I really don't know how to explain this in other words, and I'm sorry if my examples aren't clear enough. I'm a newbie and I'm italian (so my english is far from perfect). Thanks again to everyone.

In reply to Re^2: Regex matching by b_vulnerability
in thread Regex matching by b_vulnerability

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