夏夜星：有一篇文章怎么都查不到doi号。有没有哪位大神老师指导一下？[4]GudzPV,IlevanaydenovaP,CherepAV,etal.UseofStateSupportLeversforSmallandMedium-SizedEnterpriseswithintheDynamicEnvironment[J].EconomicStudiesjournal,2021。
图谋：图谋.揭秘数字对象唯一标识（DOI）.http://blog.sciencenet.cn/blog-213646-1272891.htmlEconomicStudies（IkonomicheskiIzsledvania）journalisascientificperiodicalpublishedbytheEconomicResearchInstituteattheBulgarianAcademyofSciences.In6issuesannuallyitpublishesresultsofscientificstudies,dedicatedtosignificantandinterestingcontemporaryeconomicproblems.AllpapersinthejournalareinEnglishlanguage.Theyaredouble-blindpeerreviewed.AllpapersinEconomicStudiesjournalhaveopenaccessandareintheARCHIVEsectionbelow.Since2001thepapersinEconomicStudiesareindexedandabstractedbyJournalofEconomicLiterature/EconLit,publishedbytheAmericanEconomicAssociation（AEA）,aswellasRePEc,EBSCO,SCOPUS.EconomicStudiesjournalhasSCImagoJournalRank（SJR）andisingroupQ3"Economics,EconometricsandFinance"inSCOPUS.这个刊物目前没有采用数字对象唯一标识符（DigitalObjectUniqueIdentifier-DOI），因此是不可能查到的。
夜星：谢谢王老师！晚上打扰啦！。