That depends on the subject. Biomedical influence factors are generally high, some dozens or even dozens, 3.4 is nothing at all, but if the influence factors of mechanics, control and computer are high, then the influence factors of materials science are relatively high.

The selectivity is between 0.2 and 0.3.

SCI (alias "ScienceCitationIndex") is a world-famous periodical literature retrieval tool published in institute for scientific information, USA.

It contains more than 3,700 core journals of mathematics, science, chemistry, agriculture, forestry, medicine, life science, astronomy, geography, environment, materials, engineering technology and other natural sciences published all over the world. Through strict selection criteria and evaluation procedures, the documents collected by SCI can comprehensively cover the most important and influential research achievements in the world.

In order to avoid misunderstanding, exactly, it should not be called "SCI Journal" because it is a scientific citation retrieval model.

References:

Sci—- Baidu encyclopedia