You can find peer-reviewed scientific articles in scholarly journals such as "Nature," the "Journal of Climate" and "Biochemistry." These journals are commonly available in university or other academic libraries, in online databases such as JSTOR, or directly from the journal's website.
Scholarly peer review is a process by which established experts test new knowledge in an academic field. Traditionally this process occurs anonymously, so that reviewers are not swayed by the identity of the article's author, and so that authors can not lobby on their own behalf. Peer review is considered essential to maintain standards of academic quality, and to help ensure that non-rigorous or improper scholarship is not published.