Query Operators
- AND
The AND operator is the default operator. If your query consists of a sequence of words separated by spaces, each space symbol is interpreted as an AND; e.g. optical stark effect is the same as optical AND stark AND effect This query will find all documents where all three words optical, stark, and effect appear somewhere as substrings in the text. - OR
OR is often useful for combining closely related terms like synonyms in one query; e.g. methylurea OR 598-50-5 will find all documents which contain at least one of the two strings methylurea or its CAS-Registry-Number 598-50-5. - Double quotes for phrase search
Double quotes around a sequence of words in a query only yields those documents containing the exact words in exactly this order; e.g. "optical stark effect" will produce only those documents containing exactly this phrase somewhere in the text. - BUT_NOT
BUT_NOT is used to specify documents by some relevant keyword but excluding some known context from the result-set; e.g. !urea BUT_NOT optical selects documents that contain the exact match of urea but only if it does not also contain the substring optical. - { and } for nested queries
{ and } helps to handle several valid simple queries in one single and powerful nested query; e.g. {"Ruthenium" OR "7440-18-8"} AND "magnetic flux" combines the simple query "Ruthenium" or alternatively "7440-18-8" with the required phrase "magnetic flux".
