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   25615篇
  免费   708篇
各国政治   956篇
工人农民   1064篇
世界政治   1957篇
外交国际关系   870篇
法律   15528篇
中国共产党   36篇
中国政治   194篇
政治理论   5417篇
综合类   301篇
  2020年   334篇
  2019年   364篇
  2018年   503篇
  2017年   598篇
  2016年   649篇
  2015年   479篇
  2014年   534篇
  2013年   2413篇
  2012年   606篇
  2011年   665篇
  2010年   524篇
  2009年   619篇
  2008年   716篇
  2007年   760篇
  2006年   727篇
  2005年   652篇
  2004年   647篇
  2003年   624篇
  2002年   589篇
  2001年   934篇
  2000年   859篇
  1999年   706篇
  1998年   415篇
  1997年   337篇
  1996年   320篇
  1995年   301篇
  1994年   357篇
  1993年   323篇
  1992年   497篇
  1991年   562篇
  1990年   495篇
  1989年   499篇
  1988年   487篇
  1987年   498篇
  1986年   515篇
  1985年   485篇
  1984年   422篇
  1983年   444篇
  1982年   344篇
  1981年   342篇
  1980年   261篇
  1979年   337篇
  1978年   240篇
  1977年   209篇
  1976年   185篇
  1975年   175篇
  1974年   190篇
  1973年   183篇
  1972年   149篇
  1971年   135篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
Microbial communities have potential evidential utility for forensic applications. However, bioinformatic analysis of high-throughput sequencing data varies widely among laboratories. These differences can potentially affect microbial community composition and downstream analyses. To illustrate the importance of standardizing methodology, we compared analyses of postmortem microbiome samples using several bioinformatic pipelines, varying minimum library size or minimum number of sequences per sample, and sample size. Using the same input sequence data, we found that three open-source bioinformatic pipelines, MG-RAST, mothur, and QIIME2, had significant differences in relative abundance, alpha-diversity, and beta-diversity, despite the same input data. Increasing minimum library size and sample size increased the number of low-abundant and infrequent taxa detected. Our results show that bioinformatic pipeline and parameter choice affect results in important ways. Given the growing potential application of forensic microbiology to the criminal justice system, continued research on standardizing computational methodology will be important for downstream applications.  相似文献   
962.
In the case of suspicious deaths, the technique of 1:1 taping is often used in Belgium. It consists of affixing a large number of adhesive tapes to the body of the victim. It is conventionally aimed at obtaining microtraces (e.g., fibers, hair) and is usually not used for DNA analysis. However, in some cases, DNA analysis of certain areas of interest identified on the 1:1 taping material can offer a last resort solution. The four-step method that is described in this article involves the selection of areas of interest on the body (Step 1), the selection of the corresponding tapes (Step 2), the decontamination of the tapes (Step 3), the selection of areas of interest on the tapes, for DNA sampling (Step 4). The method is illustrated by its successful application in four murder cases. In each case, DNA profiles of good quality could be identified, including profiles of persons different from the victim.  相似文献   
963.
The horizontal displacement of the human body resulting from fatal fall from a height is an important variable commonly used to inversely determine the cause or identify other forensic aspects of the fall. When examining the horizontal displacement, the wind effect is generally ignored. This technical note reports analytical modeling of the falling process, utilizing previous measurements of wind force acting on the human body, for determining the functional relationship between the wind speed and the horizontal displacement in the falling process. The result reveals that it does not take extremely rare wind conditions to cause a considerable shift of the human body, highlighting the importance to consider wind as a factor in investigations of fatal falls.  相似文献   
964.
Previous studies suggest cardiovascular pathologists are less accurate than noncardiovascular pathologists (e.g., clinical pathologists) in estimating the degree of coronary artery stenosis. To further investigate the effect of training on accurate estimation of coronary artery stenosis, we designed a study to compare the accuracy of estimates made by forensic pathologists versus medical students. Six forensic pathologists and twelve medical students each independently examined 24 images of coronary artery cross sections and gave an estimate of the degree of stenosis. When comparing all 24 images, the forensic pathologists had a median difference between the estimated percentage of stenosis and actual percentage of stenosis of −12.380 and the medical students had a median difference of −16.50 (p-value of 0.08542). In estimating the percentage of stenosis, training in forensic pathology does not guarantee significantly improved accuracy compared with medical students. Our study showed no consistent statistically significant difference between estimates given by forensic pathologists and by medical students.  相似文献   
965.
Novel psychoactive substances (NPS) are synthetic drugs that pose serious public health and safety concerns. A multitude of NPS have been identified in the United States, often implicated in forensic investigations. The most common and effective manner for identifying NPS is by use of mass spectrometry and the true utility lies within nontargeted acquisition techniques. During this study, a liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) assay was developed, validated, and implemented for forensic toxicology testing. A SCIEX TripleTOF™ 5600 + with SWATH® acquisition was used. Resulting data were compared against an extensive library database containing more than 800 compounds. The LC-QTOF-MS assay was applied to the reanalysis of biological sample extracts to discover emergent NPS. More than 3,000 sample extracts were analyzed, and more than 20 emerging NPS were detected for the first time. Among these were isopropyl-U-47700, 3,4-methylenedioxy-U-47700, fluorofuranylfentanyl, N-methyl norfentanyl, 2F-deschloroketamine, 3,4-methylenedioxy-alpha-PHP, eutylone, and N-ethyl hexedrone.  相似文献   
966.
Journal of Experimental Criminology - This paper reports a quasi-experimental evaluation of California’s 1996 medical marijuana law (MML), known as Proposition 215, on statewide motor vehicle...  相似文献   
967.

The aim of this paper is to examine the influence of the right to information laws on sustainability transparency in European local governments. This goal is novel, in that previous studies have examined the effects of various factors on the dissemination of government information (demographic, socioeconomic, political and financial) but not the contribution of legal factors to online transparency on environmental, social and economic sustainability. Our research question is this: Do information laws contribute to transparency on sustainability? Using the Global Reporting Initiative guidelines and a statistical regression analysis, we studied the websites of 106 local governments in ten European countries. The results obtained show that when transparency laws clearly stipulate the rules applicable and the procedures established for appeals, exceptions, refusals and requests, this can favour transparency on environmental, social and economic sustainability. Our findings advance understanding of this field and reinforce the basis for legal reforms to enhance sustainability transparency.

  相似文献   
968.
969.
This article describes how issue specialization through deliberative institutions called “issue publics” can improve the quality of democratic decision making. Issue specialization improves decisions by instantiating a cognitive division of labor among the mass public, which creates efficiencies in decision making and grants large groups of average citizens a scalable advantage over small groups of even the smartest and most capable individuals. Issue specialization further improves decisions by capturing issue-specific information, concentrating it within the specialized deliberative enclaves of issue publics, and refining citizens’ issue preferences. These advantages are brought to bear in wider democratic politics and policy through information shortcuts and through the specialized electoral incentives of representatives. The article responds to concerns about political ignorance, polarization/partisanship, rent seeking, and socioeconomic bias and argues that issue specialization can provide a valuable brake to polarization yet needs institutional supplementation to engage marginalized citizens and combat bias.  相似文献   
970.
Referendums are regularly criticised for reducing complex policy decisions to two maximally opposed options. This reduces opportunities for voter expression and can polarise debates. Alternative referendum designs which present more than two ballot options can offer innovative opportunities, but also raise new challenges. We can benefit by learning from previous experiences with multi-option referendum voting. Discussions of such experiences are rare and have often focussed on a limited number of cases. This article provides an overview of over 100 multi-option referendum experiences around the world. It discusses the topics on which they were held and the ballot options that were offered. It then analyses the variety in ballot design in terms of questions posed and voting methods applied. Drawing on the experiences of multi-option referendums, the article concludes with lessons that can be learned in relation to initiating and designing these referendums.  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