If you are looking for a particular reference, you may search for it in a remote database directly from EndNote. This is particularly easy when the database is publicly accessible, for example: PubMed, so that you do not need to authenticate your access. However, I would not recommend using this search function if you are performing a topic search, which should be conducted in a relevant database.
To search PubMed from EndNote:
The online search feature in EndNote 20 and later versions has been much improved, while in EndNote X9 and earlier, there are three icons: Local Library Mode, Online Search Mode (Temporary Library), and Integrated Library & Online Search Mode on the upper left corner. Users need to choose the Online Search Mode to avoid putting irrelevant references in their libraries. Below are the steps to online searching from EndNote 21 or 20:
If what you want to find is a book reference, you may search for it in the Library of Congress (LC) online catalog. To search the LC catalog from EndNote, here are the steps: