SCI (Science Citation Index) is a world-renowned journal literature search tool published by the Institute for Scientific Information.
It contains more than 3,700 core journals in various disciplines of natural sciences, such as mathematics, science, chemistry, agriculture, forestry, medicine, life sciences, astronomy, geography, environment, materials, engineering and technology, which are published all over the world. Through its strict selection criteria and evaluation procedures, SCI selects journals to provide comprehensive coverage of the world's most important and influential research results.
SCI is divided into SCI and SCI-E from the number of source journals. SCI refers to the source journals of more than 3,700 SCI print editions and SCI Compact Disc Edition (SCI CDE for short), and SCI-E (SCI Expanded) is SCI's expanded library, which includes more than 5,600 source journals, and can be accessed through international online or online journals. SCI-E (SCI Expanded) is an expanded library of SCI, containing more than 5,600 sources of journals, which can be searched through international on-line or Internet. As of June 2006, 30 SCI journals in the field of Otorhinolaryngology, Head and Neck Surgery (ENTH) are included in SCI Expanded, of which 16 are core journals (print/CD-ROM version). Being included in these 30 SCI-E journals in the specialty of otolaryngology can be called being included in SCI.