Google Books Ngram Viewer allows you to see how often phrases have occurred in the world's books over the years. Google Books has scanned over 10% of all books ever published, and now you can graph the occurrence of phrases up to five words in length from 1400 through the present day right in your browser. (1800-present is probably a better date range, as Google Books doesn't have as much material from before 1800.) Ngrams Viewer currently support the following languages:
Limiting your searches to specific domains, such as .edu or .gov., can yield more useful results. Universities and Libraries are now digitizing a lot of material in their Archives, so the .edu domain can be very effective.
From the Google homepage, click on Advanced Search.
In the Advanced Search screen, type .edu in the section that says "Search within a site or domain."
For example, here's an Advanced Search of Educational Institutions (.edu domains) ONLY for diaries, letters or memoirs from the suffrage movement:
Many public and academic libraries will have Subject Guides or a collection of links to the internet that have been reviewed and organized by Librarians. Usually, specific subject areas, such as History, have been compiled by Librarians with expertise in that field.
If you know that a certain university or institution specializes in an area of history you're interested in, investigate their web site to see if they have a list of links for that specialty.
Look for "Research Guides," "Subject Guides," "Links," etc.
A Google tool that limits your search to scholarly, academic or peer-reviewed articles.
For maximum benefit when off-campus:
Note: Google Scholar does NOT search all our databases.
Google Custom Search allows you to construct a search engine of specific web sites of your own choosing.
Once you have discovered a few web sites related to your particular area of research, combine them in a Google Custom Search.
NOTE: To create a Custom Search Engine (CSE), you will need a Google Account. If you don't have one yet, you can get one here.
Create a Custom Search Engine
Zotero is "a free, easy-to-use Firefox extension to help you collect, manage, cite, and share your research sources. It lives right where you do your work—in the web browser itself."
del.icio.us is a bookmarking system that shows you how many people have bookmarked a specific web site.
NOTE: del.icio.us won't evaluate the quality of the content on the web sites - unlike links from Libraries, which have been chosen and organized by Librarians. Still, it can be useful to see what internet sources people are using a lot.
Step 1: Use the search box in del.icio.us. This covers web page titles and very brief descriptions, not full text.
Step 2: Page through the results. You will see how many people have bookmarked the web site. The tags also can be helpful.In the example below, we see that 342 people have bookmarked The Valley of the Shadow, and that it has a Digital Library, as shown in the tags.