$ adb shell am
usage: am [start|instrument]
am start [-a <ACTION>] [-d <DATA_URI>] [-t <MIME_TYPE>]
[-c <CATEGORY> [-c <CATEGORY>] ...]
[-e <EXTRA_KEY> <EXTRA_VALUE> [-e <EXTRA_KEY> <EXTRA_VALUE> ...]
[-n <COMPONENT>] [-D] [<URI>]
...
Source : Instrumentation Testing.
And you can also check the documentation of ADB for the various options.
Have a look at this question on StackOverflow.