Journaux des marches et operations des Corps are unit war diaries. Most have survived - the major exception are those of the squadrons of the Aviation Militaire, some of which were destroyed due to enemy action in 1940, others were taken back to Berlin, where they were destroyed in 1945, while what was left was taken back to Moscow. Most of the latter have, I think, been returned to France, but there are still very few survivors. Access is free (National Archives please note).
The page you link to covers unit war diaries only. If anyone wants to check out formation war diaries as well, then there is a search page at
http://www.memoirede...earch-form.html
On the BDIC page, click on Liste des titres en ligne towards the bottom of the page. This will take you to a list of trench newspapers whose pages have been digitised and put on the web. Clicking each title will take you to that newspaper's page, where you click on an icon on the right (usually - it hasn't been done consistently ), which takes you the page images. Sometimes quirky to use, but nevertheless an immensely useful resource.
Best wishes
Ian