全文获取类型
收费全文 | 3867篇 |
免费 | 140篇 |
专业分类
各国政治 | 135篇 |
工人农民 | 130篇 |
世界政治 | 241篇 |
外交国际关系 | 125篇 |
法律 | 2677篇 |
中国政治 | 36篇 |
政治理论 | 650篇 |
综合类 | 13篇 |
出版年
2021年 | 29篇 |
2020年 | 53篇 |
2019年 | 56篇 |
2018年 | 81篇 |
2017年 | 94篇 |
2016年 | 88篇 |
2015年 | 70篇 |
2014年 | 83篇 |
2013年 | 311篇 |
2012年 | 89篇 |
2011年 | 111篇 |
2010年 | 81篇 |
2009年 | 90篇 |
2008年 | 110篇 |
2007年 | 86篇 |
2006年 | 107篇 |
2005年 | 91篇 |
2004年 | 98篇 |
2003年 | 96篇 |
2002年 | 91篇 |
2001年 | 188篇 |
2000年 | 134篇 |
1999年 | 104篇 |
1998年 | 39篇 |
1997年 | 49篇 |
1996年 | 36篇 |
1995年 | 50篇 |
1994年 | 44篇 |
1993年 | 54篇 |
1992年 | 81篇 |
1991年 | 87篇 |
1990年 | 77篇 |
1989年 | 64篇 |
1988年 | 85篇 |
1987年 | 82篇 |
1986年 | 98篇 |
1985年 | 108篇 |
1984年 | 87篇 |
1983年 | 81篇 |
1982年 | 38篇 |
1981年 | 36篇 |
1979年 | 34篇 |
1978年 | 32篇 |
1975年 | 31篇 |
1974年 | 45篇 |
1973年 | 24篇 |
1972年 | 27篇 |
1971年 | 31篇 |
1970年 | 30篇 |
1968年 | 32篇 |
排序方式: 共有4007条查询结果,搜索用时 15 毫秒
981.
982.
There have been several high profile criminal and civil cases that have been litigated in recent years involving toxicologic analyses and interpretations of blood, urine, and other specimens for drugs of abuse. Disputes have erupted between prominent toxicologists and laboratory scientists as to the validity and interpretation of the data presented. The disputes centered around the fact that the procedures used in these cases had not been properly validated with analytical noise being misinterpreted as a positive result. As with any analyses, forensic tests must be conducted in a manner such that they meet the minimum standards accepted within the toxicology community. No conclusions as to presence or absence of drug, its concentration, or its physiologic effects can be made if there is a failure to meet these basic standards. Several cases are presented where these standard tenets may not have been followed. 相似文献
983.
The authors discuss legal, ethic, and technological problems associated with introduction of drug testing by analysis of hair in Russia. There are sufficiently reliable methods of hair analysis, but lack of legal basis and poor equipment of forensic chemical departments impede the introduction and wide use of these methods in Russia. The authors propose certification of the best equipped departments and render them the legal status of regional centers for tests for narcotics and psychotropic agents. 相似文献
984.
Castella V Dimo-Simonin N Brandt-Casadevall C Mangin P 《Forensic science international》2006,156(1):70-73
The potential to recover genetic profiles from evidence samples has substantially increased since robust and sensitive amplification kits are commercially available. Nevertheless, even the best amplification kits cannot succeed when the extracted DNA is of poor quality. In this study we compared the efficiency of silica (QIAamp DNA Mini Kit), Chelex and Phenol-Chloroform (PC) based protocols to recover DNA from different categories of samples (blood and saliva on cotton swabs, muscles, cigarette butts, saliva on foods and epidermal cells on clothes). The efficiency of the QIAamp system was improved when samples were treated with QIAshredder homogenizing columns. Overall, conventional Chelex or PC protocols allowed to recover conclusive SGM Plus profiles for 61% of the samples considered in this study. Contrastingly, 82% of them were successfully genotyped after being treated with a combination of QIAshredder and QIAamp systems. Our results further suggested that the QIAshredder/QIAamp protocol was particularly helpful to analyze evidence samples with few DNA and/or that were collected on substrates containing PCR inhibitors. 相似文献
985.
Carl N. Stephan Ph.D. 《Journal of forensic sciences》2015,60(3):566-571
Facial approximation was first proposed as a synonym for facial reconstruction in 1987 due to dissatisfaction with the connotations the latter label held. Since its debut, facial approximation's identity has morphed as anomalies in face prediction have accumulated. Now underpinned by differences in what problems are thought to count as legitimate, facial approximation can no longer be considered a synonym for, or subclass of, facial reconstruction. Instead, two competing paradigms of face prediction have emerged, namely: facial approximation and facial reconstruction. This paper shines a Kuhnian lens across the discipline of face prediction to comprehensively review these developments and outlines the distinguishing features between the two paradigms. 相似文献
986.
Abstract Software companies would like to be able to control what their customers and reviewers can say about them and their software. To this end, many include in their license agreements “DeWitt” or “gagwrap” clauses which purport to prevent written reviews or disclosure of benchmark test results involving the software without the manufacturer's consent. While the courts have recognized the enforceability of software licenses to protect manufacturers, they have so far not addressed the enforceability of gagwrap clauses. This article examines gagwrap clauses and examines them in a public policy framework arising from contract and First Amendment jurisprudence. It proposes a test for the enforceability of the clauses that leaves in place many agreements not to speak but renders gagwrap clauses suspect on public policy grounds. 相似文献
987.
Sean A. Spence M.D. F.R.C.Psych. Alexandra Hope‐Urwin R.N. M.Med.Sci. Sudheer T. Lankappa M.R.C.Psych. Jean Woodhead Jenny C.L. Burgess B.Med.Sci. Alice V. Mackay B.Med.Sci. 《Journal of forensic sciences》2010,55(5):1352-1355
Abstract: Recent neuroimaging studies investigating the neural correlates of deception among healthy people, have raised the possibility that such methods may eventually be applied during legal proceedings. Were this so, who would volunteer to be scanned? We report a “natural experiment” casting some light upon this question. Following broadcast of a television series describing our team’s investigative neuroimaging of deception in 2007, we received unsolicited (public) correspondence for 12 months. Using a customized template to examine this material, three independent assessors unanimously rated 30 of an initial 56 communications as unequivocally constituting requests for a “scan” (to demonstrate their author’s “innocence”). Compared with the rest, these index communications were more likely to originate from incarcerated males, who were also more likely to engage in further correspondence. Hence, in conclusion, if neuroimaging were to become an acceptable means of demonstrating innocence then incarcerated males may well constitute those volunteering for such investigation. 相似文献
988.
Challenging DNA: Assessment of a range of genotyping approaches for highly degraded forensic samples
M. Fondevila N. Naverán M. Cerezo A. Rodríguez R. Calvo L.M. Fernández Á. Carracedo M.V. Lareu 《Forensic Science International: Genetics Supplement Series》2008,1(1):26-28
It is common in forensic casework to encounter highly degraded DNA samples from a variety of sources. In this category bone and teeth samples are often the principal source of evidential material for criminal investigations or identification of long-deceased individuals. In these circumstances standard STRs are prone to fail due to their long amplicon sizes (since DNA becomes progressively more fragmented as it degrades). To successfully resolve such cases alternative markers can be used and until recently the only other tool available was mitochondrial DNA, which despite being more resistant to degradation, is much less informative. A rapidly developing approach to analyzing degraded DNA is the typing of loci from short-amplicon PCR products based on markers such as mini-STRs and autosomal SNPs. We have performed an analysis of several cases with naturally degraded DNA using established STRs plus mini-STRs and autosomal SNPs in order to make an objective comparison of the performance of each method using challenging DNA. The main aim was to establish the benefits and drawbacks of each marker set to help the practitioner choose the DNA analysis method most suited to the circumstances of each case. 相似文献
989.
990.