Here are some useful links of databases that can help in science and advanced students.
US National Agricultural Library
Referential database with more than 3 million citations of material acquired by the National Agricultural Library of United States Department of Agriculture from 1861 to date. Full text articles available here.
Database of International Architecture
Database of international architecture, contains the records of the construction projects of important architects worldwide.
Language=In French, translation facility is available.
A freely accessible research database focusing on the relationship between human beings and the environment, with information on topics ranging from global warming to recycling to alternate fuel sources and beyond.
IMF Data: Access to regional wise microeconomic and financial data. Online statistics databases are free via the IMF eLibrary Data online portal. The databases are International Financial Statistics, Balance of Payments Statistics, Government Finance Statistics and the Direction of Trade Statistics.