Free Search Engines For Scientific and Academic Research

Overview of the following 11 scholarly search engines:

1. Google Scholar
2. CiteSeerx 
3. GetCITED 
4. Microsoft Academic Research
5. Bioline International 
6. Directory of Open Access Journals
7. PLOS ONE
8. BioOne
9. Science and Technology of Advanced Materials
10. New Journal of Physics
11. ScienceDirect 

Read more: https://www.emergingedtech.com/2013/12/top-11-trusted-and-free-search-engines-for-scientific-and-academic-research/