No you can't for the following reasons:
1) Read the dozens of posts about this over the last few weeks and months.
2) If you can see it on a web browser screen, it has already been
downloaded to the user's machine (that is the nature of how the web works,
it cannot be changed).
3) All they need to is save the page from the File menu in their browser and
they can then access it from notepad or frontpage or any other HTML editor.
Or hit Ctrl-P and print the pages from their browser.
4) Unless you disable every function of the browser (which will turn away
visitors no doubt) you're not going to stop anyone copying anything, and
even then you can disable javascript and have full functionality return.
5) The right click scripts you see around on the web can be worked around -
they are not a fool-proof method of protection since all the right-click
menu options are available from the main menus (like save picture as, or
view source etc)
6) Also there's probably no way to detect *who* took your content (even by
tracking the IP address since this is probably the IP of the ISP not the
actual user and each time the user logs on they are assigned a different IP
number).
7) I doubt a copy and paste command is "registered" as part of the
internet browser activity. So you won't know who is copy/pasting and who is
not.
Is the information so sensitive you want no one else to have it? What's to
stop someone copying it long-hand from the screen (literally, writing it
down on a note pad by hand from the screen)?