Honestly google scholar. But for my detailed in my country. Second choice were Scopus. Hehe

Dear Akram M. Altaher

As a resource platform, research gate is the best. Whereas, as an indexing platform Scopus is the most preferable one.

I use GoogleScholar first. It is very helpful and useful.

Dear Dr. Akram M. Altaher

Google Scholar is a good source of references.

Dear Dr. Akram M. Altaher

I use Google Scholar first

ResearchGate first...

Honestly google scholar. But for my detailed in my country. Second choice were Scopus. Hehe

Up to 2007, number one is PubMed, after that, any of them, nowadays Research Gate and Academia