I don't know if this works in all browsers that support browse mode. it does work in some.
I am using movement commands for the desktop keyboard layout.

Be in object review.
Use numpad 4 and 6 by themselves. 4 will move back and 6 will move forward. You are moving by word. To move by line, use 7 and 9. To move by letter, use 1 and 3.
When you get to the beginning of what you want to select, issue the command NVDA f9. Move to the end of what you want to select and issue the command NVDA f10 quickly. You should hear something indicating that text was selected. To copy text to the clipboard, issue the command twice quickly, not once.

Gene