Doing Research at the Library of Congress
IV. Keyword Searches
Sometimes there will be no formal subject heading that corresponds to
the topic you have in mind. For example, a researcher interested in "memsahibs"
(foreign women, usually British, in India's colonial period) could
find no subject heading for that topic. Another researcher looking for material
on "managing sociotechnical change" could also find no appropriate
There are several ways to get around such problems. The first
is to do keyword searches. These can be done not only in the Library's
but also in hundreds of commercial databases (covering books, journals,
newspapers, dissertations, etc.) to which the Library subscribes. Internet
search engines such as Google or Ask.com also
work via keywords. The strength of this method of searching lies in its
looking for books or articles on "managing sociotechnical change"
could instruct various databases to look for the exact word "sociotechnical"
combined with the words "manag*" or "plan*" (the asterisk
a truncation symbol); and she found numerous citations that had exactly
the words she specified.
There are two big problems with keyword searches, however, that
researchers need to take into account. The first is the problem of synonyms,
variant phrases, and different languages. The trade-off with keyword searching
is that its precise retrieval will miss variant words for the same topic.
Thus a keyword search for "business blunders" will turn up articles
those exact words, but will miss others that have words like "corporate
or "management mistakes." Similarly, a search in an exclusively keyword
database--i.e., one lacking controlled subject headings--on the words
"death penalty" will miss all of the entries that use the phrases "capital
or "legal execution." Keyword searching gives you exactly what
you specify, and if the words you think of are slightly off, you may easily
miss most of the relevant literature on your topic without realizing you've
The second problem with keyword searching shows up especially
in fulltext databases: keyword searching will very often overload
you with irrelevant results that have the right words in the wrong
contexts. (Some of these problems can be circumvented via phrase
searching using quotation marks
or other word-adjacency commands.)
In spite of its problems, however, there are situations in which keyword
searching is the best available option. Among the hundreds of databases
that allow keyword searches, several are particularly useful:
- Digital Dissertations. The Library of Congress is the only library in the
country (or the world) that owns a full set of American doctoral dissertations.
They are not recorded in the regular online catalog, however.
Searches must be done via this database instead; the UMI order
numbers that it provides are used as the call numbers for the dissertations
in the Microforms Reading Room.
- Periodicals Index Online. This is a commercial database that indexes over
4,500 periodicals in forty languages from 1665 to 1995.
- NTIS. The National Technical Information Service database is an index
to over two million federally funded research reports produced since
1964. As with doctoral dissertations, the Library of Congress is the
only library that has a full set of these research studies. They cover all
fields of knowledge, with particular strengths in the hard and social
sciences. The reports themselves are available through the Science
- Web of Science. This is an index to over 8,500 scholarly journals, internationally.
It translates the titles of foreign-language articles into
English for keyword searches.
The Library also subscribes to many full-text commercial databases, among
them Academic Search Premier, American Periodicals Series
Academic ASAP, InfoTrac OneFile, JSTOR, Project
ProQuest. These allow keyword searches, collectively, of articles
in more than 15,000 electronic journals. (Note, however, that the large majority
Library's 65,000 current periodical subscriptions are not available electronically;
they can be read only in paper copy or microfilm formats.) Online
listings of which electronic journal titles are available, through which subscription
services, are provided by databases such as Serials Solutions, TDNet,
A list of
current database subscriptions is
available on the Library's website. Please note that most of these resources
are available only on Library premises. Consult the Library's reference staff
for recommendations on databases relevant to your research. All of these databases
allow keyword searches (some also allow searches
by subject headings); and the list is continually growing.