Web of Science (WoS) is an excellent cross-disciplinary database. WoS's Core Collection is one of several databases we have on their platform. The others show if you click the the dropdown arrow beside Web of Science Core Collection. That will allow you to search all the databases we have from this vendor at once, or you may select and search in Inspec, Medline, or Zoological Record individually. See the Selecting a Database page for an illustration.
The Web of Science Core Collection contains: Science Citation Index, Social Sciences Citation Index, Art and Humanities Citation Index, and an Emerging Sources Citation Index. You may search these individually; you can also set a custom time span to search, below the search boxes.
The journals included in Web of Science are selected based on specific criteria, summarized by the publisher as "including but not limited to how often articles from the journals are cited, whether the journals are published in English, whether they conform to common publication standards in terms of format and citation," and so on.
As a general rule, the journals indexed in WofS are the top ten percent of the most-cited journals in a given discipline or field. It is not an all-inclusive or comprehensive index to any field.
The journals that they index change over time, as research emphases and publications change. It is fairly easy to discover which journals are being indexed in a given year, through the Journal Citation Reports, but relatively difficult to see the whole list of thousands of journals. There is a 'master journal list' that you may look at if you have a WoS account.
Note: many of the citation results, such as with cited author searches, are based on all the journals in all the databases we subscribe to through this vendor, rather than just Web of Science.
Registering in Web of Science allows you to save and re-run searches, create alerts, and makes it easier to tag and send records. It allows you to use EndNote Basic through their site. You may also create a ResearcherID profile under your login.
Web of Science is derived from citation indexes which provided information about cited authors and works when no other abstracting and indexing tool did. That has changed, but Web of Science is still a leader in the field.