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   12243篇
  免费   326篇
各国政治   696篇
工人农民   447篇
世界政治   843篇
外交国际关系   465篇
法律   7669篇
中国共产党   2篇
中国政治   155篇
政治理论   2169篇
综合类   123篇
  2020年   147篇
  2019年   170篇
  2018年   246篇
  2017年   256篇
  2016年   279篇
  2015年   220篇
  2014年   248篇
  2013年   1324篇
  2012年   309篇
  2011年   442篇
  2010年   294篇
  2009年   297篇
  2008年   346篇
  2007年   342篇
  2006年   322篇
  2005年   275篇
  2004年   329篇
  2003年   343篇
  2002年   270篇
  2001年   492篇
  2000年   448篇
  1999年   386篇
  1998年   164篇
  1997年   116篇
  1996年   124篇
  1995年   115篇
  1994年   122篇
  1993年   128篇
  1992年   215篇
  1991年   234篇
  1990年   229篇
  1989年   226篇
  1988年   249篇
  1987年   238篇
  1986年   231篇
  1985年   217篇
  1984年   208篇
  1983年   202篇
  1982年   114篇
  1981年   86篇
  1980年   91篇
  1979年   124篇
  1978年   108篇
  1977年   87篇
  1976年   91篇
  1975年   86篇
  1974年   86篇
  1973年   85篇
  1972年   87篇
  1971年   90篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A 3-year-old child died of the combined effects of a bacterial superinfection and a relative overdose of hydrocodone prescribed for a cough due to a presumed viral respiratory tract infection. This case illustrates the importance of evaluating the effects of prescribed medication in assessing the cause and mechanism of death in children dying suddenly of presumed natural disease.  相似文献   
992.
Abstract: To determine the prevalence and circumstances of psychoactive substances amongst nonoverdose completed suicide, 1436 consecutive cases autopsied at the NSW Department of Forensic Medicine over the period 1/1/1997–12/31/2006 were analyzed. Substances were detected in 67.2% of cases, and illicit drugs in 20.1%. Alcohol was present in 40.6% of cases. Males were more likely to be positive for alcohol, cannabis, and psychostimulants, and females for pharmaceuticals. Illicits were associated with younger age. Alcohol was most prominent amongst toxicity cases, as were opioids, psychostimulants amongst gunshot cases, and pharmaceuticals amongst drownings. Cases in which drug and alcohol histories were noted were more likely to have a substance detected. Alcohol was more common where a suicide note was left and where relationship problems were involved. Pharmaceuticals were more common where a previous attempt was noted. Licit and illicit substances are strongly associated with suicide, even when the method does not involve drug overdose.  相似文献   
993.
Hemoperitoneum is usually due to rupture, laceration, or perforation of a blood vessel or organ. The author describes three deaths due to massive intra-abdominal hemorrhage, all in alcoholics with cirrhosis of the liver, in which no source for the bleeding was found. One of the three individuals, who was briefly hospitalized, showed evidence of a disseminated intravascular coagulopathy (DIC). In the author's opinion, this is the most likely cause of the intra-abdominal hemorrhage in the two other cases and is related to the cirrhosis of the liver.  相似文献   
994.
995.
996.
There are a number of forensic cases in which the identification of the epithelial cell type from which DNA originated would provide important probative evidence. This study aimed to develop a technique using histological staining of fixed cells to distinguish between skin, buccal and vaginal epithelium. First, 11 different stains were screened on formalin-fixed, wax-embedded cells from five women. Samples were analysed qualitatively by examining staining patterns (colour) and morphology (absence or presence of nuclei). Three of the staining methods – Dane's, Csaba's and Ayoub-Shklar – were successful in distinguishing skin epithelial cells from buccal and vaginal. Second, cells were smeared directly onto slides, fixed with one of five fixatives and stained with one of the three stains mentioned above. Methanol fixation, coupled with the Dane's staining method, specific to keratin, was the only technique that distinguished between all three cell types. Skin cells stained magenta, red and orange and lacked nuclei; buccal cells stained predominantly orange–pink with red nuclei; while vaginal cells stained bright orange with orange nuclei and a blue extracellular hue. This staining pattern in vaginal cells was consistent in samples collected from 50 women aged between 18 and 67. Identification of cell type from unlabelled micrographs by 10 trained observers showed a mean success rate of 95%. The results of this study demonstrate that histological staining may provide forensic scientists with a technique for distinguishing between skin, buccal and vaginal epithelial cells and thus would enable more conclusive analyses when investigating sexual assault cases.  相似文献   
997.
998.
999.
Recent developments in German corporate governance   总被引:1,自引:0,他引:1  
This paper provides an overview of the German corporate governance system. We review the governance role of large shareholders, creditors, the product market and the supervisory board. We also discuss the importance of mergers and acquisitions, the market in block trades, and the lack of a hostile takeover market. Given that Germany is often referred to as a bank-based economy, we pay particular attention to the role of the universal banks (Hausbanken). We show that the German system is characterised by a market for partial corporate control, large shareholders and bank/creditor monitoring, a two-tier (management and supervisory) board with co-determination between shareholders and employees on the supervisory board, a disciplinary product–market, and corporate governance regulation largely based on EU directives but with deep roots in the German codes and legal doctrine. Another important feature of the German system is its corporate governance efficiency criterion which is focused on the maximisation of stakeholder value rather than shareholder value. However, the German corporate governance system has experienced many important changes over the last decade. First, the relationship between ownership or control concentration and profitability has changed over time. Second, the pay-for-performance relation is influenced by large shareholder control: in firms with controlling blockholders and when a universal bank is simultaneously an equity- and debtholder, the pay-for-performance relation is lower than in widely held firms or blockholder-controlled firms. Third, since 1995 several major regulatory initiatives (including voluntary codes) have increased transparency and accountability.  相似文献   
1000.
Abstract: The primary purpose of this article is to investigate the factors that predict the efficiency of residential recycling collection services in Canadian local governments. The findings are based on a survey of 128 residential recycling producers from all regions of Canada. One of the most significant findings is the lack of a relationship between private‐sector companies collecting recyclables and the overall efficiency of collection operations. The dominance of the private‐sector collection of recyclables (over seventy‐seven per cent of all producers were contracted companies) does not translate into greater efficiencies. The most important variables in the model are amenable to local control. They include tonnes collected per vehicle per year, requiring full bins, inclusion of composting operations in the overall recycling program, the number of different kinds of materials recycled, participation rate, and reliance on side‐loading collection vehicles. Among the direct predictors of unit costs, the key underlying factor is the productivity of residential recycling operations. Because recyclables are marketed, handling them takes time, reduces the weights that collection vehicles can carry, and generally reduces productivity. Even diligent efforts to improve productivity will not bring recycling costs down to the levels for residential solid‐waste collection. Sommaire: L'objectif principal du présent article est d'examiner les facteurs qui prévoient l'efficacité des services de collecte de produits recyclables résidentiels dans les municipalités canadiennes. Les résultats reposent sur un sondage réalisé auprès de 128 producteurs de collecte de produits recyclables résidentiels opérant dans toutes les régions du Canada. L'un des résultats les plus notoires est le manque de relations entre les sociétés du secteur privé qui récupèrent les produits recyclables et l'efficacité d'ensemble des opérations de collecte. La prédominance de la collecte de produits recyclables par le secteur privé (plus de soixante‐dix‐sept pour cent de tous les producteurs étaient des sociétés contractuelles) ne se traduit pas par une plus grande efficacité. Les variables les plus importantes du modèle peuvent faire l'objet d'un contrôle local. Elles comprennent les tonnes récupérées par véhicule par an, l'exigence de poubelles pleines, l'inclusion d'opérations de compostage au programme général de recyclage, le nombre de différentes sortes de matériaux recyclés, le taux de participation, et le recours à des camions de collecte à chargement latéral. Parmi les variables explicatives directes des coûts unitaires, le principal facteur sous‐jacent est la productivité des opérations de recyclage résidentiel. Comme les produits recyclables sont commercialisés, leur manutention prend du temps, réduit le poids que les camions de collecte peuvent transporter, et réduit d'une manière générale la productivité. Même des efforts diligents pour améliorer la productivité ne feront pas baisser les coûts du recyclage aux niveaux de ceux de la collecte des déchets solides résidentiels.  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