When trying to build a search query, you may want to use a specific classification code to either refine your results or specifically find patents that have this particular classification code. There are various ways to do this, these include:
1. Use the refinement filters: Once you have reached the search results page after completing your search, you can use the filters on the left-hand side of the screen to refine your results using specific classification codes, as seen in the image below (You can find out more about the refine options here: How Do I Use The Refine Options On The Results Page?):
2. Use the classification code helpers: From the field search page, you can select the classification code helpers which if you type a keyword into them you will be given a number of suggestions of classification codes related to your search, these can then be added to refine your search. You can find out more about the classification code helpers here: How Do I Use The Classification Code Helpers?
3. Use the classification search: Using the classification search you are able to search using a keyword for all the classification codes of that type that contains the inputted keyword. From this, you can search for all the patents that have a specific classification code. You can find out more about the classification search here: What Is Classification Search?