Journal Impact Factors
Citation Counts and Journal Rankings Competing Services:
Refereed Journals
Primary research is often published in a peer-reviewed journal. Look for the referee jersey icon - 
in Ulrich's Periodical Directory---
What's the H-index?
Devised by Jorge Hirsch, the H-index is the highest number of papers an author has that have each received at least that number of citations. This may be fairer than counting total papers or just high-ranked articles, and can't be self-inflated. Someone with an h-index of 10 has written 10 papers that each had at least 10 citations.
Beware Predatory Journals
Beall's List at ScholarlyOA.com lists publishers and journal titles that are deceptive in their publishing practices (charge author fees, do not practice peer-review, and do not "count" in promotion review). Always check with your advisor before submitting a manuscript for publication - they know the best journals.