However, by entering 1995 in the Year field, for example, the total number of records found can be reduced to approximately 40 records, all published in 1995. The system will process a search in the order the prompts appear on the screen. For example, in the sample search shown below, the system first finds all the records with alcohol dehydrogenase in the descriptor field, then narrows the results by year. This search will result in 400 records found. However, this search, will find approximately 40 records.
Boolean operators canbe used for more powerful searching within one field.
To use boolean operators in a field, use the following symbols. Within a field, search criteria are evaluated from left to right. Using parentheses within the field can change the order that the search engine processes the criteria. Between fields, search criteria are evaluated from left to right and top to bottom. If all the search prompts have the Boolean operator AND in the drop-down boxes, the results of a search are the same regardless of the evaluation order.