After you open The Help Window and Topic-Based Help, click the Search button () to open the search engine and search the HTML content. Search results are shown sorted by product. You can also search in the contents of The Documentation Window.

On the Documentation window, you can adjust the Search scope (see Figure 1-1). Enter a search term in the Search expression field and then select All documents, Selected only, or Application library from the list to narrow or expand the search scope as needed. For Selected only (Figure 1-3), first click a branch in the tree (for example, COMSOL Multiphysics Reference Manual) and then the search includes all the documents below the selected node until the beginning of the next branch. In this example it searches until the end of the Troubleshooting License Errors section.