首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12549篇
  免费   394篇
各国政治   537篇
工人农民   476篇
世界政治   907篇
外交国际关系   399篇
法律   7632篇
中国政治   78篇
政治理论   2807篇
综合类   107篇
  2020年   143篇
  2019年   209篇
  2018年   256篇
  2017年   302篇
  2016年   281篇
  2015年   210篇
  2014年   261篇
  2013年   1252篇
  2012年   287篇
  2011年   349篇
  2010年   265篇
  2009年   340篇
  2008年   326篇
  2007年   346篇
  2006年   336篇
  2005年   320篇
  2004年   306篇
  2003年   323篇
  2002年   308篇
  2001年   458篇
  2000年   406篇
  1999年   328篇
  1998年   195篇
  1997年   156篇
  1996年   164篇
  1995年   165篇
  1994年   163篇
  1993年   153篇
  1992年   252篇
  1991年   266篇
  1990年   261篇
  1989年   261篇
  1988年   246篇
  1987年   238篇
  1986年   270篇
  1985年   272篇
  1984年   245篇
  1983年   225篇
  1982年   158篇
  1981年   134篇
  1980年   121篇
  1979年   155篇
  1978年   90篇
  1977年   114篇
  1976年   101篇
  1975年   74篇
  1974年   92篇
  1973年   87篇
  1972年   80篇
  1971年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
This study examined whether sexual abuse was related to higher levels of psychological distress among incarcerated youth and if the effects were invariant across gender. Participants were male and female adolescents, aged 11 to 20 years, incarcerated in six juvenile correctional institutions in five states. Using data from a national study of juveniles confined to secure institutions, this study assessed the relationship between gender, sexual abuse, and depression. Adolescents who were sexually abused during childhood compared to adolescents who were not report higher levels of depression. Sexually abused girls and boys report higher levels of depression compared to boys not sexually abused. These findings suggest the importance of understanding the relationship between childhood sexual abuse and depressive symptoms among incarcerated youth. Additionally, the findings suggest that the effects of childhood sexual abuse are similar for males and females among a high-risk sample of institutionalized juvenile delinquents. Implications for treatment of incarcerated youth are discussed.  相似文献   
922.
923.
924.
A total of 137 urine samples and 46 serum samples, corresponding to 154 self-confessed designer drugs consumers in Ibiza island, were analyzed for the presence of designer drugs: amphetamine and amphetamine derivatives (methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), methylenedioxyamphetamine (MDA), p-methoxymethylamphetamine (PMMA), p-methoxyamphetamine (PMA), etc.), ketamine and gamma-hydroxybutyric acid. Among this population, coming both from the forensic clinic and from the emergency room of a hospital, a total of 99 cases were found positive for some designer drug. This study shows the prevalence of methylenedioxymethamphetamine (MDMA) among designer drug users, sole or in association with other drugs. Also, the mixture of MDMA with other designer drugs, ethanol and/or cocaine is shown to be more likely to produce toxic symptoms requiring clinical attendance in a hospital emergency room. These findings along with the consumption history, the concentrations of drugs and metabolites in urine and serum and the toxicological significance for the interpretation of some MDMA metabolites such as 4-hydroxy-3-methoxymethamphetamine (HMMA) are discussed in this study.  相似文献   
925.
Downstairs falls frequently occur within domestic environments and are mainly associated with elderly and intoxicated individuals, often feature multiple injuries on various parts of the body. In most cases it is not possible to determine the cause of the fall and/or death solely by means of external examination. In this retrospective study, which covers a period of 11 years, all cases of death which included a fall downstairs in their case history, were collected from the Forensic Institutes of the Universities of Bonn and Greifswald, Germany. Falls downstairs made up to 2% (166 cases) of all postmortem examinations carried out within this period. Interestingly, almost double of the amount of such falls applied to males as to females. The primary cause of death was cranio-cerebral trauma and the vast majority of skull injuries associated with falls downstairs were found above 'the hat brim line'. Injuries were also often found on several other parts of the body at once. Nineteen of the 116 examined individuals exhibited agonal injuries. In these cases, postmortem examination revealed pre-existing disease or intoxication to be the cause of death and thus, cause of the fall. The injury pattern only allows a tendency towards vital or agonal incident as a conclusion.  相似文献   
926.
927.
Poppy seeds contain morphine in different amounts. Reported concentrations are up to 294 mg morphine/kg poppy seeds. Since penalties based on Street Traffic Law (parapgraph 24a StVG) in Germany (administrative offence) require definitive proof of morphine in blood samples, and the "Grenzwertkommission" in consultation with the Ministry of Transportation recommended a threshold of free morphine of 10 ng/mL, the question arose whether the consumption of poppy seeds can lead to a blood concentrations equal or higher than 10 ng/mL of free morphine. Therefore, five volunteers ate poppy seed products (50 mg morphine/kg poppy seeds). In urine, all on-site tests were enzyme immunologically positive for opiates and were positive to morphine by GC/MS. All the blood samples were negative to morphine by EIA and to free morphine by GC/MS. However, after hydrolysis, morphine was detected by GC/MS in all cases. Accordingly, in Germany, penalties based on parapgraph 24a StVG are not likely to cause road users any concerns should they have consumed poppy seeds. Driver Licensing Authorities, however, should be advised of this problem to avoid unjustified legal measures.  相似文献   
928.
Reticuline (a precursor of opium alkaloids) was detected and characterised as its trimethylsilyl ethers, acetyl esters and methyl ethers by GC-EIMS and GC-CIMS in opium and the urine of opium users after hydrolysis by acid or beta-glucuronidase as coextractive of morphine. Because this compound cannot be detected in heroin and poppy seeds, it is suggested as a differentiating marker between opium and heroin use, opium and poppy seeds use, or opium and "pharmaceutical" codeine use in cases when opiate use has been confirmed by detection of morphine and codeine in the urine. As well as being a constituent of opium, reticuline in the urine of opium users may also result from the metabolic demethylation of the three other benzyltetrahydroisoquinoline opium alkaloids: codamine, laudanosine and laudanine.  相似文献   
929.
Some previous research indicates that confidence affects the accuracy of probabilistic clinical ratings of risk for violence among civil psychiatric inpatients. The current study investigated the impact of confidence on actuarial and structured professional risk assessments, in a forensic psychiatric population, using community violence as the outcome criteria. Raters completed the HCR-20 violence risk assessment scheme for a sample of 100 forensic psychiatric patients. Results showed that accuracy of both actuarial judgments (HCR-20 total scores) and structured professional judgments (of low, moderate, and high risk) were substantially more accurate when raters were more confident about their judgments. Findings suggest that confidence of ratings should be studied as a potentially important mediator of structured professional and actuarial risk judgments.  相似文献   
930.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号