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The purpose of this step is to take your broad topic and narrow it down to what you are specifically looking for so you can write your thesis/specific purpose statement. You want to look for subtopics or additional search terms in this step.
You can try searching the internet, using the Content Box in Wikipedia or search other encyclopedias to help narrow down your topic. You can not normally cite these sources for academic research (check with your professor), however they are great resources for narrowing down your topic.
PubMed is a service of the U.S. National Library of Medicine that includes over 17 million citations from MEDLINE and other life science journals for biomedical articles back to the 1950s. It includes links to selected full text articles and other related resources
Video shows ophthalmic medical personnel how to perform a variety of basic tests. Topics include: history taking, visual acuity, neutralization of spectacles, color vision, confrontation visual fields, formal visual fields, evaluation of pupils, keratometry, slit-lamp assessment of angles, applanation tonometry, pachymetry, clinical optics, ocular motility, pediatric exam, instrument maintenance, sterile technique, and patient services