Press "HELP" and go to "Controls" to see all the buttons:
Construction Shortcuts
"W" Select the Weapons Tab.
"5" Select the Systems Tab.
"E" Select the Experimentals Tab.
"1,2,3,4,5,6" Select the associated unit in the active tab.
Unit Control
"Left Mouse Button" Select a unit.
"Right Mouse Button" or "Space" Cancel current selection.
"Q" Toggle the active/inactive state of the selected unit.
"A" Toggle the armed/unarmed state of the selected unit.
"X" Destroy the selected unit.
"CTRL-#" Assign a group number to selected units.
"SHIFT-#" Recall a group number.
"CTRL-0" Remove selected units from any group.
"F" Toggle formation movement.
Other Shortcuts
"R" Press and hold to see through terrain.
"I" Toggle display of top Information bar.
"Arrow-Up" or "G" Scroll the map up.
"Arrow-Down" or "B" Scroll the map down.
"P" Pause or resume the game.
"F1" Switch from/to windowed mode.
"CTRL-C or SHIFT-C" Quick Save.
"CTRL-V or SHIFT-V" Quick Load.
"Backspace" Take a screen-shot of the entire map.