Sorting and Searching:
Zotero also allows you to organize you citations with tags.
By default, Zotero will automatically add subject headings and keywords as tags when importing items from a library catalog or database. (This can be turned of in the Zotero preferences if you wish.)
To manually add or remove tags for a source, select the item in the center column and the Tags column in the right column. Click Add to add new tags and the minus signs to remove tags.
To manage and search by tags, use the tag pane in the bottom half of Zotero's left column.
Clicking a tag here will display all items with this tag. Selecting multiple tags will display only items having that combination of tags. The Filter box can be used to search your tags.
You can also delete or rename a tag on all your citations (good for consolidating tags) by right-clicking on the tag.