A few examples of online encyclopedia articles. An encyclopedia or review article can give you an overview of a topic and a rich list of references.
PubMed and Medline are about the same underlying database, but with different interfaces. PubMed gets new articles earlier.
There's no magic way to the truth. Science (and reality) is hard.
Questions -- Does this information agree with other sources? What did researchers do to learn this? (Do they explain their methods, at least.)
One shortcut -- Use "peer reviewed" or scholarly sources. But not everything that survives this process is TRUE. (See the first video below.) Some databases let you select only academic or peer-reviewed articles. Others, like PubMed, Science Direct, and Web of Science, are about 100% peer-reviewed. You can usually tell an article is academic/peer reviewed by the author credentials at beginning and references at end.
Checklist methods: (See the second video.) How relevant to my topic? How recent? Who wrote and published it? Do they have credentials? Are they trying to sell me something? Are there any other obvious sources of bias or lack of credibility?
"Track" citations! Does your source refer to previous sources? Look for those sources. Also, since it was published, has anyone cited your source? (Google Scholar is good for this, and Web of Science originated the "Cited by" function.)