Can I change isolation level in Oracle?

I'm writting a transaction in Oracle. Can I change isolation level within t开发者_StackOverflow中文版his transaction for one select statement? Now I have Read Commit, and I want within transaction change this once to serializable and next back to the read commit.

Best Regards, Gregory

---

In SQL, you can use the SET TRANSACTION statement

For example:

set transaction isolation level serializable;  
set transaction isolation level read committed;