There are two databases in particular that are critical for the Middle East: the Encyclopaedia of Islam and Index Islamicus.
Due to the lack of comprehensive works on the Middle East, the Encyclopaedia of Islam is generally the starting point when researching a topic. Articles in the Encyclopaedia are written by leaders in the field and provide an overview of the state of each topic. They also provide a bibliography of the core works on that topic.
Index Islamicus is the only database that focusses 100% on the Middle East. It covers some, but not all Western language journals published in the U.S. and Europe, and some books.
These databases include information on parts of the Middle East, or are in the process of development and will gradually include more relevant information. They can be helpful, but are not a good place to start for every paper.