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Ge/ESE 170: Microbial Ecology: Getting Started

A short guide to resources for students taking Ge/ESE 170 at Caltech.

Google and Google Scholar

In A Nutshell

Google Scholar Search Tips:

  1. Use secondary sources and other articles to develop vocabulary for better search terms.
  2. Use the "Cited by" to see newer articles referencing your chosen article.
  3. Results sorting is limited to relevance or date.

In Depth

Google suffers from two basic problems:

  1. It is web-based, and thus won't index anything that isn't web-accessible (i.e. anything in print).
  2. It is based (to a large extent) on popularity - search results aren't based necessarily on content relevancy, but rather on how many other pages link to them, or how many other people have clicked on a link after doing the same search.

Using Google (and Google Scholar to an extent) will search all types of web sources, not just scholarly ones. It's important to know how to evaluate what you're looking at.

Scholarly databases are better because:

  1. They are more narrow in scope than Google (so you get more relevant results more easily). For example, searching for "plasma" in a Biology-oriented database is more likely to give results having to do with the blood component rather than the state of matter.
  2. They utilize controlled vocabulary.

Article Types

Literature databases usually index several kinds of scholarly writing.

  • Original Research Article
    This is the standard peer-reviewed "journal article" that reports on an actual experiment performed, and presents the results of those experiments. These articles generally contain the following clearly-defined sections: Background/Introduction, Experimental/Methods, Results/Discussion, Conclusion. If what you are reading doesn't contain all of those sections, it probably isn't an Original Research Article.

  • Review Article
    Reviews present summaries and critiques of OTHER work that has been done on a topic, but it does NOT present original experimental results. It does not follow the format of an Original Research Article, and may or may not be peer-reviewed.

  • News/Opinion/Editorial Article
    These are popular in trade publications, such as Chemical & Engineering News, and also in scholarly journals such as Science and Nature. They are usually good as overviews of a particular research experiment, but don't give the full scope of the work, and are NOT peer-reviewed. Usually, the Original Research Article is referenced somewhere in the text.

  • Book or Book Chapter
    After ideas and experiments have been established in the open literature for a while, work may be collected and published in a book. Edited books usually contain several chapters dealing with different aspects of a topic. The editor of the book is usually a prominent researcher in the field, and invites other researchers to contribute chapters. Edited book chapters are more similar to Review Articles than Original Research Articles.

  • Thesis / Dissertation
    These are written in completion of a Master's or Doctorate degree. Sometimes, thesis chapters may appear in peer-reviewed journals as independent articles. They are not always easily available.

  • Patent
    Patents are legal documents that protect the intellectual property of the inventor. It gives the inventor the exclusive right to use their invention for a limited amount of time in exchange for making the idea publicly available (as a patent).

Preferred / Controlled Vocabulary

In A Nutshell

Two sources that will help you learn preferred vocabulary:

1. Scholarly articles sometimes (but not always) have a section in the full text labeled Keywords, usually near the Abstract, or at the end of the article under additional information - here's an example - look just at the bottom of the page.


2. Use a literature database such as Web of Science, PubMed, or SciFinder. All these databases show you groupings of preferred vocabulary when you search, although they are called slightly different things in each one.

It should be noted though that Google Scholar, as great as it can be, doesn't offer any help with discovering preferred terminology - it recommends reading secondary sources!

In Depth

You probably know that there are certain preferred words used to describe different things, usually under different circumstances. This is true of both scientific disciplines and databases. For example, take the word plasma. If you asked a physicist to define it, you'd probably get something different from what a biologist or doctor would say (i.e. a state of matter, versus a component of blood).

So, it's important to become familiar with the way concepts and techniques are described in your field of interest. The best way to do this is to read, read, and read some more! Pay attention to the way ideas and experiments are described in the literature. For example, in medicine, you've probably heard of the term "heart attack". Searching for that in the medical literature might get you some articles, but you'd soon discover (especially if you're using PubMed - more on that later) that the preferred term in the medical community is "myocardial infarction". Similarly, in the chemical community, common names of chemicals (for example, polyacetylene) are being phased out in favor of IUPAC names (polyethyne), but if you want to find older articles as well as newer articles, you need to know both!

Boolean Searching

In A Nutshell

  • AND: Forces your search results to include all terms connected by AND
  • OR: Search results will include any of the terms connected by OR (but not necessarily all)
  • NOT: Search results will include the first term but not the term following NOT
  • Quotes: Forces search results to include the exact wording between quotation marks

In Depth