CrossRef Metadata Search is simply a web interface tacked onto the "SIGG" search backend that powers the Ubiquity and Blog plugins. Please note that:

• "CrossRef Metadata Search" is not the same thing as "CrossRef Search". Instead, CrossRef Metadata Search is focused on allowing researchers to lookup citations using only terms that might appear in the bibliographic metadata of the item they are searching for.
• SIGG is not a traditional fulltext search engine. It is designed specifically to lookup citations in Crossref metadata and, as such, it does not do stemming, term-expansion or other optimizations that you might expect of a normal seacrh engine.
• CrossRef metadata does not include abstracts. SIGG is only searching titles, authors, publisher names, etc.
• The SIGG search engine is very experimental and you should be aware that it can sometimes (often?) return the wrong item. Also note that the index only includes journal articles and conference proceedings. It does not yet contain books.
• There is currently a 20 item limit on the number of hits returned per query. This might seem arbitrary and stingy, but please remember- we are not trying to create a full-blown search engine- we are just trying to create a citation lookup service. Of course, if, after looking at how the service is used, it looks like we need to up this limit, we will.

With those warnings in mind,here is the (very simple) search interface.

Also note that, if you are running FireFox or similar, you can install an OpenSearch Description File and access the CrossRef Metadata Search from your browser's search interface.