For 2018, h5-index for Nature of 365 means that 365 articles published in Nature in 2013-2017 have received at least 365 citations each.
Step 1. Go to https://scholar.google.com/
Step 2. Click on the icon
to display more options.
Step 3. Select Categories and Subcategories (if needed) to display Journals and their h5-index and h5-median