Using Boolean operators will retrieve more focused search results
AND -To obtain articles about breast cancer during pregnancy, combine the "exploded" MeSH term "PREGNANCY" with AND ""BREAST NEOPLASMS"
OR - To searcch for articles about either nosebleeds or heatstroke in children at summer camp, combine the MeSH terms: ("EPISTAXIS" OR "HEAT STROKE") AND "CAMPING" AND "CHILD"
NOT - For searching the topic of "zirconium used for knee implants," you might discover that most of the literature refers to zirconim used for oral surgery in dental work. To eliminate those citations, combine the MeSH term, "ZIRCONIUM" AND "KNEE" NOT "SURGERY, ORAL"