Boolean operators (and, or, not), Nesting with parentheses, and Truncation symbols (*) can be used to develop more complex search queries. These queries can be entered directly into the Search box. Quotation marks can be used around phrases to retrieve documents containing the exact phrase.
|birth defect*||retrieval set includes coverage of birth defect or birth defects|
|birth defects and folic acid||retrieval set includes content covering birth defects and folic acid in the same document|
|birth defects or folic acid||retrieval set includes either content covering birth defects or content covering folic acid|
|birth defects not folic acid||retrieval set includes content that covers birth defects where folic acid is not covered in the document|
|(neural tube defects or birth defects) and folic acid||retrieval set includes content where either neural tube defects or birth defects is covered and prevention with folic acid is covered in all content|
|"neural tube"||retrieval set includes content where the exact phrase neural tube appears in the document|