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   11918篇
  免费   137篇
各国政治   452篇
工人农民   402篇
世界政治   969篇
外交国际关系   460篇
法律   7473篇
中国共产党   1篇
中国政治   57篇
政治理论   2197篇
综合类   44篇
  2021年   78篇
  2020年   217篇
  2019年   267篇
  2018年   264篇
  2017年   333篇
  2016年   340篇
  2015年   284篇
  2014年   298篇
  2013年   1120篇
  2012年   266篇
  2011年   344篇
  2010年   308篇
  2009年   324篇
  2008年   319篇
  2007年   282篇
  2006年   306篇
  2005年   279篇
  2004年   266篇
  2003年   260篇
  2002年   267篇
  2001年   483篇
  2000年   440篇
  1999年   306篇
  1998年   199篇
  1997年   164篇
  1996年   135篇
  1995年   129篇
  1994年   153篇
  1993年   144篇
  1992年   207篇
  1991年   224篇
  1990年   209篇
  1989年   222篇
  1988年   207篇
  1987年   194篇
  1986年   237篇
  1985年   214篇
  1984年   163篇
  1983年   174篇
  1982年   123篇
  1981年   128篇
  1980年   91篇
  1979年   134篇
  1978年   83篇
  1977年   78篇
  1976年   75篇
  1974年   76篇
  1973年   68篇
  1972年   69篇
  1970年   47篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
911.
Abstract: The University of Mississippi has a contract with the National Institute on Drug Abuse (NIDA) to carry out a variety of research activities dealing with cannabis, including the Potency Monitoring (PM) program, which provides analytical potency data on cannabis preparations confiscated in the United States. This report provides data on 46,211 samples seized and analyzed by gas chromatography‐flame ionization detection (GC‐FID) during 1993–2008. The data showed an upward trend in the mean Δ9‐tetrahydrocannabinol (Δ9‐THC) content of all confiscated cannabis preparations, which increased from 3.4% in 1993 to 8.8% in 2008. Hashish potencies did not increase consistently during this period; however, the mean yearly potency varied from 2.5–9.2% (1993–2003) to 12.0–29.3% (2004–2008). Hash oil potencies also varied considerably during this period (16.8 ± 16.3%). The increase in cannabis preparation potency is mainly due to the increase in the potency of nondomestic versus domestic samples.  相似文献   
912.
Abstract: An online forensic dental identification exercise was conducted involving 24 antemortem–postmortem (AM–PM) dental radiograph pairs from actual forensic identification cases. Images had been digitally cropped to remove coronal tooth structure and dental restorations. Volunteer forensic odontologists were passively recruited to compare the AM–PM dental radiographs online and conclude identification status using the guidelines for identification from the American Board of Forensic Odontology. The mean accuracy rate for identification was 86.0% (standard deviation 9.2%). The same radiograph pairs were compared using a digital imaging software algorithm, which generated a normalized coefficient of similarity for each pair. Twenty of the radiograph pairs generated a mean accuracy of 85.0%. Four of the pairs could not be used to generate a coefficient of similarity. Receiver operator curve and area under the curve statistical analysis confirmed good discrimination abilities of both methods (online exercise = 0.978; UT‐ID index = 0.923) and Spearman’s rank correlation coefficient analysis (0.683) indicated good correlation between the results of both methods. Computer‐aided dental identification allows for an objective comparison of AM–PM radiographs and can be a useful tool to support a forensic dental identification conclusion.  相似文献   
913.
Das deutsche Bodenschutzrecht ist angesichts seines geringen Anwendungsbereiches sowie seiner sehr lückenhaften und zudem vollzugsunfreundlichen Konkretisierung in Grenzwerten h?ufig wenig effektiv. Diese These verfolgt der vorliegende Beitrag anhand eines besonders wesentlichen, in der politischen, juristischen und naturwissenschaftlichen Debatte bisher kaum beachteten gesundheits- und umweltrelevanten Faktors: der düngungsbedingten Belastung von B?den durch Uraneintr?ge. Dies verhilft zugleich zu einer n?heren Bestimmung der konkurrierenden Anwendungsbereiche verschiedener Umweltgesetze.  相似文献   
914.
Possibilities of a complex study of the damage to the body and clothes caused by shots from non-lethal arms (unstem gun PB-4 from a complex Osa) are illustrated by real expert tasks from forensic medical practice. A combination of experimental shots with emission spectral analysis of the objects of the study and targets is validated for determination of the patron characteristics and composition as well as shooting diastance.  相似文献   
915.
A widespread presumption in the law is that giving jurors nullification instructions would result in "chaos"-jurors guided not by law but by their emotions and personal biases. We propose a model of juror nullification that posits an interaction between the nature of the trial (viz. whether the fairness of the law is at issue), nullification instructions, and emotional biases on juror decision-making. Mock jurors considered a trial online which varied the presence a nullification instructions, whether the trial raised issues of the law's fairness (murder for profit vs. euthanasia), and emotionally biasing information (that affected jurors' liking for the victim). Only when jurors were in receipt of nullification instructions in a nullification-relevant trial were they sensitive to emotionally biasing information. Emotional biases did not affect evidence processing but did affect emotional reactions and verdicts, providing the strongest support to date for the chaos theory.  相似文献   
916.
Bromethalin is a neurotoxin found in some rodenticides. A delusional 21-year-old male presented to a hospital with altered mental status the day after ingesting a bromethalin-based rodenticide. He died 7 days after his self-reported exposure to c. 17 mg bromethalin (equivalent to 0.33 mg bromethalin/kg). His clinicopathologic course was characterized by altered mental status, obtundation, increased cerebrospinal fluid pressure, cerebral edema, death, and diffuse histologic vacuolization of the white matter in the central nervous system seen on microscopic examination at autopsy. The presence of a demethylated form of bromethalin in the patient's liver and brain was confirmed by gas chromatography with mass spectrometry. Clinical signs and lesions observed in this patient are similar to those seen in animals poisoned with bromethalin. This case illustrates the potential for bromethalin ingestion to result in fatal human poisoning.  相似文献   
917.
The DNA commission of the International Society of Forensic Genetics (ISFG) was convened at the 21st congress of the International Society for Forensic Genetics held between 13 and 17 September in the Azores, Portugal. The purpose of the group was to agree on guidelines to encourage best practice that can be universally applied to assist with mixture interpretation. In addition the commission was tasked to provide guidance on low copy number (LCN) reporting. Our discussions have highlighted a significant need for continuing education and research into this area. We have attempted to present a consensus from experts but to be practical we do not claim to have conveyed a clear vision in every respect in this difficult subject. For this reason, we propose to allow a period of time for feedback and reflection by the scientific community. Then the DNA commission will meet again to consider further recommendations.  相似文献   
918.
As drug arrests and jail overcrowding added pressure to increase pretrial release in localities during the 1980s and 1990s, the need to manage a larger and higher-risk pretrial population of defendants awaiting adjudication in the community became a high priority for justice agencies. In the late 1990s Philadelphia officials sought to discover the ingredients of a successful supervision strategy through four interlinked field experiments to provide an empirical basis for a major reform of the pretrial release system. The results of the linked randomized experiments question common assumptions about “supervision,” its impact and effectiveness, about the underlying nature of the noncompliant defendant, and deterrence implications. The study emphasizes the importance of interpreting the findings in the context of implementation of the policy reform. Findings suggest that facilitative notification strategies wield little influence on defendant behavior and that deterrent aims are undermined by the system's failure to deliver consequences for defendant noncompliance during pretrial release. The most significant contribution of the article is its illustration of a major evidence-based policy reform undertaken by a major court system.  相似文献   
919.
Intimate partner violence (IPV), an international public health matter, is linked to psychological distress including suicidal behavior. Despite the noted sequelae associated with IPV, many individuals display resilience in the face of IPV exposure. This study examines two potential protective factors in the IPV-suicidal ideation link, namely existential and religious well-being, in a sample of African American women. Low-income, African American, female suicide attempters who were abused by a partner within the previous year (N?=?111) were administered the Conflicts Tactics Scale-2, Spiritual Well-Being Scale, and Beck Scale for Suicide Ideation. Mediational models testing indirect effects through the bootstrapping method revealed that the total effect of IPV on suicidal ideation was positive and significant, confirming suicidal ideation as a consequential outcome of IPV among African American women. This effect was mediated by existential well-being; however, religious well-being was not a significant mediator, suggesting that existential well-being serves a unique protective role in the IPV-suicidal ideation relation. The results provide additional support for the well-known positive effects of existential well-being on mental health among African American samples. Culturally-informed, meaning-making interventions to enhance existential well-being appear to be effective in reducing suicidal ideation in this population.  相似文献   
920.
We examine the understudied link between mental/physical health problems and their relationship with perceived unsafety via higher levels of vulnerability. We examine this relationship by linking data at the individual-level, the neighborhood-level, and the county-level using the Portraits of American Life Survey (PALS). Using this data we examine the effect of individual and neighborhood conditions on perceived safety while controlling for county-level crime rates. Findings indicate that higher numbers of physical impairment and mental health issues are independently related to higher levels of perceived unsafety. Both mental and physical health problems are associated with higher levels of fear. These higher levels of vulnerability then directly contribute to higher levels of feeling of unsafety. Unlike past research, we find a mental health link to fear of crime that cannot be explained by physical impairments.  相似文献   
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