Scopus, EI/Compendex, Chemical Abstracts Service/SciFinder, ChemWeb, Google Scholar, TOC Premier, EBSCO, Suweco CZ, CNKI Scholar, Genamics JournalSeek, MediaFinder®-Standard Periodical Directory, PubsHub, Index Copernicus, J-Gate, Ulrich's Periodicals Directory and JournalTOCs.