What makes for an adequate research base and what constitutes a bibliography for a research project that would indicate effort in its compilation,...

To figure out if you've covered the available research on a subject adequately, and therefore if you have a sufficient research base, you should look at the parameters or outlines of your research question. Have you answered all parts of the question? If the question is chronological in nature, for example, have you covered all parts of it? If the question is about several countries, have you included all of them in your answer? If the question is about the effects of an historical event, have you included a range of political, social, and economic effects from a variety of perspectives? If your research has contradicted your thesis, you should revise your thesis accordingly. In addition, your research should provide an overview and historical context for the subject or event you are covering. For example, if you are writing about a battle in the Civil War, you should include what else was going on in the war at that point. 

To write your bibliography, you should include every source you used and write down information about each source as you're using it, including page numbers. Following the guidelines set out by your teacher or professor, you should cite each source (using MLA, APA, or Chicago format). While there is a lot of research available today, a good researcher chooses high-quality sources. That means that not all the sources are available from doing an internet search. Instead, a high-quality bibliography includes books, articles from databases, and even primary and archival sources (primary sources are those written at the time of the event you are studying). High-quality sources also often include a consideration of the author and a selection of authors who are authorities on a subject. 

If you are writing about historiography, meaning the way historians have written about an event, be sure to include multiple perspectives. One way to do this is to use the footnotes and references in each source to find new sources. A good paper about historiography will include a range of perspectives and will sift through competing ideas or claims to locate the biases or shortfalls that the ideas may contain. In other words, an historiography paper has to make sense of contradictory ideas and explain why historians may disagree.

Finally, using a source such as Purdue OWL (see the links below), a well-done bibliography includes properly cited sources that are formatted correctly. It also may include annotations in the case of an annotated bibliography. This means that each source is evaluated or explained. Your bibliography should also be up-to-date, meaning that the sources should reflect the most important recent research in that subject area, as well as older works.