While conducting a literature search, citation management tools allow you to create libraries where you can store your results.
Import References: EndNote, Zotero, RefWorks
If you are working on multiple projects that you need to keep separate, or if you want to separate out your references by different categories, options are provided to help you create navigable sub-folders and/or separate libraries.
Organize References: EndNote, Zotero, RefWorks
You can also set up shared libraries that allow for group editing:
Share References: EndNote, Zotero, RefWorks