RussiaUniversitiesStudentsSubstance Abuse, IntravenousDrug UsersUnsafe SexNeedle SharingSexual PartnersRisk-TakingResearchHeterosexualityHIV InfectionsSexual BehaviorSexually Transmitted DiseasesHospitals, UniversityCross-Sectional StudiesResearch Support as TopicPrevalenceResearch DesignEthics, ResearchResearch PersonnelNursing ResearchTranslational Medical ResearchHealth Services ResearchGenetic Research