Zenon, the catalogue of the Deutsches Archaologisches Institut. Much of the same information as DYABOLA below, only through a free interface.
Included in this catalog are not only books held by the libraries, but a full index to the journals and collected volumes. You can also search by the DYABOLA subject headings (the "Systematic Access to the DAI Bibliographies (Thesaurus)" link).
"Search" allows keyword and browse (alphabetical list) searches. Results will be books or articles; results that are articles will have an "Uplink" link that will take you to the record for the journal or collected volume, from which a "downlink" will take you to the full table of contents of the volume. There is good coverage of Greek Turkish archaeolog. This catalogue is in Unicode, so you can search for Greek titles in Greek.
A group of literature and object databases that offers subject catalogs of publications on the history of art and the ancient world. Includes the subject catalogs of the German Archaeological Institute in Rome, the Bibliography of Iberian Archaeology from the German Archaeological Institute in Madrid, and the Archaeology of Roman Provinces from RGK Frankfurt.