, ▁cit ations ▁are ▁included ▁from ▁member ▁soci eties , ▁and ▁select ively ▁chosen ▁American ▁journ als . ▁Cit ations ▁become ▁typically ▁available ▁online ▁on ▁the ▁same ▁date ▁as ▁the ▁corresponding ▁journal ▁article . ▁ ▁S ources ▁Over all , ▁the ▁source ▁cit ations ▁are ▁derived ▁from ▁material ▁published ▁by ▁the ▁A IP ▁and ▁member ▁soci eties , ▁ ▁which ▁are ▁English - spe aking , ▁Russian , ▁and ▁Ukrain ian ▁journ als ▁and ▁conference ▁proceed ings . ▁C ertain ▁American ▁physics - related ▁articles ▁are ▁also ▁sources ▁of ▁cit ations . ▁About ▁ 6 0 ▁journ als ▁have ▁cover ▁to ▁cover ▁indexing , ▁and ▁about ▁ 1 0 0 ▁journ als , ▁overall , ▁are ▁indexed . ▁ ▁S cope ▁Sub ject ▁coverage ▁en comp ass es ▁the ▁following : ▁▁ ▁App lied ▁physics , ▁Elect romagnet ic ▁technology , ▁Micro elect ron ics ▁ ▁At omic ▁physics ▁and ▁M ole cular ▁physics ▁ ▁Bi ological ▁physics ▁and ▁Medical ▁physics ▁ ▁Class ical ▁physics ▁and ▁Quant um ▁physics ▁ ▁Cond ensed ▁matter ▁physics ▁ ▁Element ary ▁particle ▁physics ▁ ▁General ▁physics , ▁Opt ics , ▁Ac oust ics , ▁and ▁Fl uid ▁dynamics ▁ ▁Ge oph ys ics , ▁Astronom y , ▁Ast ro physics ▁ ▁Material s ▁science ▁ ▁N uc lear ▁physics ▁ ▁Pl asma ▁physics ▁ ▁Phys ical ▁chem istry ▁ ▁See ▁also ▁List ▁of ▁academic ▁databases ▁and ▁search ▁engines ▁ ▁References ▁ ▁External ▁links ▁A IP ' S ▁SP IN ▁Database ▁Re aches ▁One ▁Mill ion ▁Records .