Looking at this panel, you also can click on the keyboard shortcuts button and change the default keys for many menu functions and actions. There is also a PDF of the shortcuts which can be downloaded from the Scribus website. Below are the English defaults, all of which can be changed.
See also: Mouse Usage Hints
Ctrl + S = Saves Document
Ctrl + W = Close Document
Ctrl + O = Open Existing Document
Ctrl + P = Open Print Dialog
Ctrl + I = Show Document Info
Ctrl + Q = Quit Scribus
Ctrl + C = Copy
Ctrl + V = Paste
Ctrl + X = Cut
Ctrl + K = Delete
Ctrl + A = Select all
Ctrl + Z = Undo
Ctrl + L = Align Left
Ctrl + E = Align Center
Ctrl + R = Align Right
Ctrl + D = Duplicate Object
Ctrl + G = Group Objects
Ctrl + U = Ungroup Objects
Ctrl + H = Lock / Unlock Objects
Ctrl + 1 = Actual Size 100%
Ctrl + 0 = Fit in Window
F10 toggles on and off all palettes
F11 toggles on and off all guides, frames and grids.
Alt + - = "Smart" Hyphen
Ctrl + # = Insert Page Number ** Depending on your keyboard layout you should change this default to an F key. I use F7. For 10-99 pages, use Ctrl + ##, for 100-999 pages, use Ctrl + ###
F12 = Insert Special Unicode Character as Hex e.g 0020
when editing a text frame on the page.
Shift + Left Click = Selecting more than one object.
Shift+Cursor Key selects Characters
Ctrl+Shift+Cursor Key selects Words
Ctrl+Cursor Up/Down selects Lines
Ctrl+Home selects Text from the Start to the Cursor Position
Ctrl+End selects Text from the Cursor Position to the End
Ctrl+Cursor Key moves to the next Word
Home moves to the beginning of the line
End moves to the end of the line
Ctrl+Shift+Click selects the Object beneath another
Shift+Click adds an Object to the Selection
Ctrl+Alt+Click selects a single Object out of a Groups
You can constrainobjects when re-sizing them with Ctrl-drag. Constraining keeps the aspect ratio the same as the original shape.