Five years ago, in the article As we may search – Comparison of major features of the Web of Science, Scopus, and Google Scholar citation-based and citation-enhanced databases Peter Jacso from the Department of Information and Computer Science, University of Hawaii, compared several indexes, particularly Google Scholar (G-S). The article found G-S to have too many flaws. He concluded:

“Unfortunately, G-S gives a bad name to autonomous citation indexing. It shows lack of competence, and understanding of basic issues of citation indexing. G-S fails even in implementing the most basic Boolean OR operation correctly. Riding on the waves of the regular Google software which is great for processing the unstructured heap of billions of Web pages, G-S cannot handle even the meticulously tagged, metadata-enriched few million journal articles graciously offered to it by many publishers for free.”

In my opinion, no much has changed since then. That’s why I use G-S as my last option. I prefer public scholar search resources to get at no cost articles not found in G-S or that otherwise I would need to pay from journal indexes. Some of these free resources are designed to get a pdf version of the manuscripts sought. More than one university and private company prefer to have its own open source index available to anyone, but blocking Googlebot.