Is this what you are expecting?

Code:
SQL> insert into delme values ('abcdef'); 

1 row created.

SQL> insert into delme values ('adfavs');

1 row created.

SQL> insert into delme values ('cdefab');

1 row created.

SQL> insert into delme values ('fecdab');

1 row created.

SQL> insert into delme values ('adfbce');

1 row created.

SQL> 
SQL> select * from delme where instr(name,'cde') > 0;

NAME
---------------------------------------------------------
cdefab
abcdef

SQL> 

This contains "cde"


SQL> select * from delme where ( instr(name,'c') > 0 
  2  and instr(name,'d') > 0 and instr(name,'e') > 0 ); 

NAME
---------------------------------------------------------
cdefab
fecdab
adfbce
abcdef

SQL> 

This contains "c" and "d" and "e"
Sameer