SQL> startup restrict mount;
ORACLE instance started.

Total System Global Area  835104768 bytes
Fixed Size                  2232960 bytes
Variable Size             666897792 bytes
Database Buffers          163577856 bytes
Redo Buffers                2396160 bytes
Database mounted.
SQL>
SQL> select name, open_mode from v$database;

NAME      OPEN_MODE
--------- --------------------
TEST      MOUNTED

SQL> drop database;

Database dropped.

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL>