- The 'All keywords (AND)' option will return records with all of the keywords (keyword1 AND keyword2 AND keyword3).

- The 'One or more keywords (OR)' option will return records with at least one of the keywords (keyword1 OR keyword2 OR keyword3).

- Use general keywords for more results and specific keywords for fewer results. For example, a search using the keyword 'soil' will return all records with the word soil or soils, but a search using the keywords 'soils' will only return records containing the word soils. A search for 'hydro' will return all records containing 'hydro' (hydrology, ecohydrology, hydrologic, etc.).