The best replacement for pubmed is medline.

The best alternatives to pubmed are rated as following:
★★★★★  medline
★★★  ovid
★★  google scholar
★★  cinahl
★★  pubmed central
★★  scopus
★  pmc
★  sciencedirect
★  embase
★  cochrane
  ovid medline
  web of knowledge
  ebsco
  web of science

Your alternative for pubmed is not listed? Suggest!
Speaking about pubmed, one probably shouldn't forget about full text.

Other search terms related to pubmed and their ratings are:
★★★★★ full text
★ endnote
You have in mind a companion for pubmed and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of pubmed in all years. Click on graph for more.
pubmed
medline
ovid