ArXiv

arXiv (pronounced "archive"—the X represents the Greek letter chi [χ]) is an open-access repository of scientific pre-prints.Pre-prints are scientific articles before being approved by peer review. Pre-prints which has been approved by peer-review are academic journals.  All documents are stored as PDF.
Importance
Generally, all scientific journals have peer-review procedures. This process sometimes take several years. The time lag made by this process will easily cause delay to the scientific community. arXiv was made to avoid this delay.
Usage at Wikipedia etc.

Wikipedia and some journals accept citations by arXiv. Some academic search engines (such as Google Scholar) can help users to find arXiv pre-prints.
Scientific areas
arXiv includes pre-prints from various scientific fields such as:
 Computer science
 Artificial intelligence
 Machine learning
 Mathematics
 Algebraic geometry
 Numerical analysis
Statistics
 Physics
Similar websites
Today, there are several arXiv-like websites in other areas.
 bioRxiv: This is the biology version of arXivAbdill, R. J., & Blekhman, R. (2019). Meta-Research: Tracking the popularity and outcomes of all bioRxiv preprints. Elife, 8, e45133.Loew, L. M. (2016). Peer review and bioRxiv. Biophysical journal, 111(3), E01.
ChemRxiv: This is the chemistry version of arXivKidd, R., Koch, W., Milne, J., Sens, I., Tegen, S., Wilson, E., ... & Brennan, M. (2018). ChemRxiv: Year One and Beyond. ChemRxiv (2018).
 EarthArXiv: Earth science & planetary science version of arXivJackson, C. (2018). EarthArXiv-A preprint server for the Earth and Planetary Sciences. EGUGA, 1429.
 medRxiv: Medicine version of arXiv. It includes many pre-prints about COVID-19.
 SocArXiv: Social science version of arXivCohen, P. (2016). Developing SocArXiv: a new open archive of the social sciences to challenge the outdated journal system. Impact of Social Sciences Blog.
Further reading









References and notes

 Other websites 


  - Unofficial bot
 arXiv Vanity - converts the arXiv LaTeX sources to HTML.
 ar5iv  - an arXiv Lab converting the LaTeX sources to HTML. 

Category:1991 establishments in the United States
Category:American science websites
Category:Archives