How to access help pages from SQL*Plus prompt?

Does SQLPlus provide the help pages for its commands? Is there a way to access the help text from the 开发者_C百科SQLPlus prompt, like this text for STARTUP?

I tried

SQL> man startup
SP2-0734: unknown command beginning "man startu..." - rest of line ignored.
SQL> startup -help
SP2-0714: invalid combination of STARTUP options
SQL> startup --help
SP2-0714: invalid combination of STARTUP options
SQL>

Try:

SQL>HELP STARTUP

From the Oracle docs:

To access command-line help for SQL*Plus commands, type HELP or ? followed by the command name at the SQL command prompt.

The syntax for HELP in Oracle SQL Plus is

HELP topic (Topic is an SQL PLUS command or HELP COMMANDS)