Examples: |
Results: |
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 |