Screenshot demonstrating PubFocus functional elements. A) PubFocus search menu containing basic, advanced and detailed sub-menus. B) Hyperlink-based search limiting tools allow interactive search output navigation. Four hyperlinks are commonly provided with AND, OR, NOT and ONLY operators. C) Corresponding impact factor (IF) of the journal and a number of forward citations are shown for each record. D) Drop-down menu allows selection of forward citations source to be used in further analysis: PubMed Basic, PubMed Central or Google™ Scholar. E) Interactive navigation tool allows quick back and forth focusing on the subsets of the initial search using temporary local database. F) Drop-down menu allows viewing of search results sorted by either: publication date, first author, last author, impact factor, forward citations or PIF (aka Combined Impact Factor). Sorting can be done either in ascending or descending modes. G) Combined Impact Factor is calculated for each record based on Publication Impact Factor (see Implementation). H) Ranking tables provide semi-graphical output of the search results categorized by various bibliometric parameters (see Implementation section). Ranking tables contain limiting tools (hyperlinks, check-boxes) allowing selection and analysis of various subsets of the initial search records. I) "NCI Ontology" tool outputs terms from NCI thesaurus occurring within titles and/or abstracts of the relevant citations. Terms are presented in semi-graphical form. It includes search limiting tools (hyperlinks, check-boxes). J) "Gene Orthology" tool outputs terms from MGD mammalian gene orthology database occurring within titles and/or abstracts of the relevant citations. Terms are also presented in semi-graphical output including search limiting tools (hyperlinks, check-boxes).