It's not hard to find inconsistencies and flaws in Google Scholar. Some of them follow below.
This search on semiconductors is an example from Peter Jacso Google Scholar and The Scientist 2005 (Published on university homesite as extra material).

In this reference it seems like the article is published 2006, but checking the source shows it's published 1990 and 2006 is the starting page of the article:

Searching advanced search limiting the date range to 1995-2006 returns 135,000 hits. But extending the date range to 1985-2006 returns just 131,000 hits. How come, Google Scholar?

Another flaw in Google Scholar is the OR Boolean operator. In this case the result for: dahlqvist OR dahlquist is 16.200 which means there should be 500 documents with both dahlqvist AND dahlquist, otherwise 16.700. But it's not.

This is a quotation from Peter Jasco "As we may search" in Current Science Vol. 89, No. 9. (10 November), pp. 1537-1547.:

"G-S is a free service, and for many who consider it to be a gift for the world it may be anathema to say any but good words of it. It is also to be emphasized that it is a joint gift by some publishers and/or their digital facilitators (the content part), and Google (the software and the service operation part). If ISI or Elsevier could have received such unfettered access to the publishers’ archives for harvesting their sites offering standard-compliant metadata, they could probably sell their services – if not for free – at a fraction of their current price. Building a multi-million record database incurs multi-million dollar investment just to subscribe to the journals, administer their processing, and record their standard bibliographic data, abstract, and descriptors, for about 1 million papers per year in the most recent period".