What are subject headings?
When you search the Internet for something you are usually performing a keyword search; that is, you type in the word or words that must be present in the results.
When you search the library online catalog (OPAC) for something you are usually performing a subject search; that is, you type in a word and the computer searches to see if that word has been assigned as a subject heading, or descriptor, to any books in the library collection.
In other words, a keyword search for "medicine" on the internet would bring up every page that has the word medicine in the text somewhere, while a subject search on the OPAC would bring up a list of every book that is about medicine, whether or not the word medicine appears in the title.
A good way to keep subject headings and keywords straight is to remember that subject headings are conceptual while keywords are literal.
Can you search by subject on the Internet?
It is possible to do subject searches on the Internet. Search directories such as Yahoo, Lycos, and the Librarian's Index to the Internet classify information by subject. One, the Internet Public Library, even uses dewey decimal classification to organize its subjects, just like real public libraries!
Do print periodical indexes use subject headings or keywords?
Most print periodical indexes use standard subject headings to organize the citation information, so when you search in a print index you must remember to think conceptually about your topic. Once you find your broad topic there may be narrower sub-headings that help you find more specific information.
Here is an example from a page of the Social Sciences Index that shows the subject headings and how citations are organized under those headings. This is what you would find if you looked up the term "medicine".
Medications
See Drugs
Medicinal Herbs See Herbs Therapeutic Use
Medicinal Plants
Cultural conservation of medicinal plant use in the Ozarks.
J.M. Nolan and M.C. Robbins. bibl Hum Organ v58 no1 p67-72
Spr 1999
Medicinal foods; cross-cultural perspectives. C. H. Chen and D.C.
Volding. Bibl Drugs Soc v15 no1/2 p49-64 1999
Medicine
See Also
Alternative Medicine
Chiropractic
Communication in Medicine
Family Medicine
Geriatrics
Health
Health Professionals
Health Resorts, Spas, etc.
Hospitals
Nurses
Nursing
Nursing Homes
Obstetrics
Pediatrics
Physicians
Psychiatry
Surgery
Tropical Medicine
Economic Aspects
See Medical economics
Philosophy
The enigma of health; Hans-Georg Gadamer at 100. F. Dallmayr.
Bibl f Rev Polit v62 no2 p327-50 Spr 2000
Practice
See also
Diagnosis
Home visiting (medicine)
Medical Errors
Medical Referral
Empirical support for psychological assessment in clinical health
care settings. T.W. Kubiszyn and others. Bibl Prof Psychol
Res Pract v31 no2 p119-30 Ap2000
(There are many more sub-headings and entries after this, but this should be enough to give you the general idea)