There are literally tens of thousands of journal titles published all over the world in different fields and subfields, and in different languages. As a rule, there is a manageable number of important journal titles in a particular field or subfield. All the journals publish papers in accordance with a long-accepted practice called peer review. Two or more reviewers anonymously review every paper submitted for publication, and must agree that the paper warrants publication. The journals thus serve as the first line of information.
New findings appear in the refereed journals first.
And interesting new data or findings generally lead to repetition and refinement of the information by other scientists who may also publish papers on the subject. For the most part, journals publish papers that contain something novel or different, and that represent the results of original research efforts. A lot of the stuff is pretty trivial, but it is generally novel, and adds to the total base of knowledge and information. The next level in the information hierarchy consists of reviews. Reviews may sometimes be whole books, or may be chapters of books, or review papers published in the journals.