The old 'exp' utility does provide many options and can get you backup of tables and triggers ONLY (not sequence or any other type objects).
Pls use advanced 'expdp' (data pump) for better options. You can use 'INCLUDE or EXCLUDE' object switch to meet your goal.
INCLUDE and EXCLUDE
The INCLUDE and EXCLUDE parameters can be used to limit the export/import to specific objects. When the INCLUDE parameter is used, only those objects specified by it will be included in the export/import. When the EXCLUDE parameter is used, all objects except those specified by it will be included in the export/import. The two parameters are mutually exclusive, so use the parameter that requires the least entries to give you the result you require. The basic syntax for both parameters is the same.
INCLUDE=object_type[:name_clause] [, ...]
EXCLUDE=object_type[:name_clause] [, ...]
The following code shows how they can be used as command line parameters.
expdp scott/tiger@db10g schemas=SCOTT include=TABLE:"IN ('EMP', 'DEPT')" directory=TEST_DIR dumpfile=SCOTT.dmp logfile=expdpSCOTT.log
expdp scott/tiger@db10g schemas=SCOTT exclude=TABLE:"= 'BONUS'" directory=TEST_DIR dumpfile=SCOTT.dmp logfile=expdpSCOTT.log
Pls check out for more details...
http://www.oracle-base.com/articles/10g/oracle-data-pump-10g.php#IncludeExclude