A person can't keep up to date with all fields of science. Therefore, a person has to pick certain areas of science that they have an interest in and keep up to date in that specific area.
There are millions of journal articles published over a year. So it's impossible to read them all. If you want to know the leading research in the biological sciences, you will want to read PNAS, cell, Nature, Genome Research, Science, Molecular Cell, Nature Genetics (all of the Nature Review journals), American Journal of Human Genetics, Clinical Investigation, EMBO, FASEB, and many others.
I have a journals send me the e-TOC in my email. So when I get new journal e-TOC's in my email, I open up the TOC and look over the titles and then pick out the interesting journal articles that I like and those that could be applied to the type of research I want to do in the future. I have thousands of journals that get sent to my email, and I usually find an article in every journal issue that I find interesting or is related to my field of interest.
To be a great scientist (not average), a person has to know their field inside and out.
If you want the latest information about a specific topic, what most scientist do (which I do as well), is go to pubmed and type in the subject you want the latest information on, or you set up a personalized account with pubmed and have new journal articles that are related to a specifc topic be sent to your email every day.
I have set up an account with pubmed and I get new journal article sent to me every day that are related to genetics syndromes and birth defects (the terms I used were dysmorphology and teratology.