Provided by a vendor named Elsevier, Science Direct is, as its name suggests, our best database for researching scientific topics. However, it's also great for social science (education, psychology) and business topics.
All journal articles in Science Direct are scholarly. The books in Science Direct are also scholarly. However, reference works and images cannot be considered scholarly.
When you first log into Science Direct:
To get to the advanced search screen, click the Advanced Search link, which is in small print, way over to the right of the Basic Search boxes.
Click on the title of the article to get to the Article Information page, where you will find:
Science Direct almost always has the full-text. The exceptions are articles that are still in pre-publication status. Because they are not published yet, they will not be available through Google Scholar or any of the other library databases either.
Articles are available in HTML full-text. You can find them by scrolling down below the Abstract in the Article Information page, and you can also navigate from section to section and from image to image using the Outline on the left side of that page.
Articles are also available as downloadable PDF files. PDFs are formatted exactly the same as the paper version. If you want to print an article, you should download the PDF first, and then print. (You will need to have software to open PDF files, such as Adobe Reader.)
Science Direct lets you download (save) the PDF full-text from two locations. One is right under the article in the search results list. See below.
The other is at the top of the Article Information page. See below.