Public Health

Web of Science
Broad database that is most useful for the 'harder' end of the social sciences (e.g. psychology), health sciences, and natural sciences. This is a good place to look for intervention studies. It is also useful for evaluating the relative importance of a particular article to the field. 

PubMed (same data, different skin as Medline / Ovid)
This is the premier source for medical research; You can often find medical intervention studies here. Created by the US National Library of Medicine, it contains references to authoritative information on medicine, nursing, dentistry, veterinary medicine, the healthcare system, pre-clinical sciences, and much more. Note: PubMed is a public portal into the same underlying data which is in the Medline/Ovid databases. These other databases, which are meant for medical professionals, have more advanced options but are less user friendly.

Pacific Library - Boxer Search 
Pacific's library search includes millions of items, including both electronic and print material. All of our books and e-books are here, as well as about 80% of the journal articles that we have paid access to. This is the quickest way to get into sources that you can access immediately, without having to guess whether you'll be able to get the full text.

Google Scholar
This database gathers sources from many other databases into one centralized location. It will find nearly any academic book or article that has been published. The downside is that it is so large, that the items you really want to find may be buried under dozens of irrelevant sources. Also, there may be many articles that you cannot actually open. [LINK See More Tips on setting up and using Google Scholar.]

Proquest Dissertations and Theses
This database is an amazing resource for dissertations (which are the final papers of Ph.D. and Master's students, typically 50-250 pages long). This is a great place to find cutting edge research on recent issues as well as in-depth literature reviews. These sources are generally very difficult to find except through this database!

ERIC 
The best database for studies related to education. You can often find studies related to school-based interventions here.

Academic Search Premier
A good general-purpose database that indexes over 13,000 periodicals with coverage in the social sciences, humanities, education, physical sciences, technology, medicine, etc. Full text is available for nearly 5,000 titles.

Agricultural & Environmental Science Collection (Proquest)
A good general database for researching environmental topics: This database includes the renowned AGRICOLA, TOXLINE, ESPM (Environmental Sciences and Pollution Management) and Environmental Impact Statements (EIS) databases and provides full-text titles from around the world, including scholarly journals, trade and industry journals, magazines, technical reports, conference proceedings, and government publications.