Use MeSH to:
Example: Search the word "nursing" in PubMed and your results will vary between the profession and breastfeeding. Using the apporpriate MeSH term will eliminate this confusion:
"Nursing [MeSH]" = The field of nursing care concerned with the promotion, maintenance, and restoration of health.
"Breast Feeding [MeSH]" = The nursing of an infant at the breast.
Note: Searching with only MeSH terms excludes the most current citations in process and publisher-supplied citations as they are not indexed with MeSH.