ProQuest is a large American information provider. ProQuest provides access to content used in teaching, learning and research, including scholarly journals, dissertations, ebooks, newspapers, periodicals, and historical collections.
ProQuest is not a publisher. Instead, it is what is known as an aggregator. Aggregators provide access to content created by publishers. Everything available on ProQuest has been published elsewhere, ProQuest collects material from different publishers and makes it available on one platform, so it can create subject-specific platforms like Computer Science Database. The problem with aggregators, however, is that content can change over time. Publications can go from full text to bibliographic data (title and abstract) only to being removed from the platform all together. This doesn't happen very often but it's important to note that it can happen.
Computer Science Database gives users access to top Computer Science publications titles with full text often, but not always available. There are millions of records coming from a variety of sources.
Subject coverage includes:
Most of the content spans from 1980-present, but there are earlier documents and articles.
Content includes:
Publications can also be browsed or searched through the Publications link on the home page.
Articles include all charts, tables, diagrams, and other graphical elements.
ProQuest use a service named UnPaywall to try to maximise full text availability. If full text is not available on Computer Science Database, but is available elsewhere, you'll see 
in the article record on the search results page and
in the article record page.
Unpaywall is described in more detail in the Open Scholarly Resources section and its browser extensions for Firefox and Chrome are recommended
