You can search databases such as these for journal articles. Most provide article citations and abstracts. In many cases, you will also be able to access full text articles.
This comprehensive handout from the library at Angelo State University How To Recognize Peer Reviewed (Referred) Journals offers useful advice on distinguishing between scholarly and other types of journals.
Among other advice, they recommend also consulting Ulrich's directory.
Many of the databases that you will use come from Ebsco, a provider of online indexes and full text.
These brief tutorials describe the searching strategies that work best in databases such as CINAHL and SportDiscus. You will need Adobe Flash Player to view them.
Creating a Basic Search (Ebsco)
Advanced Search (Ebsco)
These online tutorials are specific to health sciences databases.
CINAHL Basic Searching (Ebsco)
CINAHL Advanced Searching (Ebsco)
PubMed Tutorials (National Library of Medicine) Several tutorials ranging from basic to advanced searching and MeSH term searching.