SCI, SSCI and EI are three different evaluation systems for academic journals, each with different emphasis and evaluation criteria.

1.sci (science citation index) is a comprehensive citation index database of sci-tech journals published by institute for scientific information (ISI), which mainly contains original research papers on basic theory and applied technology in natural science. SCI focuses on the evaluation of basic scientific research, emphasizing originality and innovation.

2. SSCI (Social Science Citation Index) is a social science citation index and comprehensive social science journal citation index database published by institute for scientific information (ISI), which mainly includes original research papers in the field of social science. SSCI pays attention to the evaluation of social science research, emphasizing theory and demonstration.

3.EI(EngineeringIndex) is a citation index database of engineering journals published by American EngineeringInformationInc, which mainly contains original research papers in the field of engineering technology. EI focuses on evaluating the research in the field of engineering technology, emphasizing practicality and technicality.

Generally speaking, SCI, SSCI and EI are all important indicators to measure the quality and influence of academic journals, but the emphasis and evaluation criteria are different. SCI pays more attention to the originality and innovation of basic science research, SSCI pays more attention to the theoretical basis and enthusiasm of social science research, and EI pays more attention to the practicality and technicality of engineering technology research.