Pubget is like Pubmed, except you get the PDFs right away:

Simple search: nik gene cluster

Title and abstract: centrality[tiab] hub[tiab] network[tiab]

Latest issue: plos biol[latest]

Authors: carroll sb[au] AND (rokas[au] OR gompel[au]) NOT kassner[au]

Citation: chisholm sw[au] nature[ta] 2003[dp] 424:1047

Happy searching—wherever you are!