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   719篇
  免费   38篇
各国政治   51篇
工人农民   71篇
世界政治   49篇
外交国际关系   34篇
法律   375篇
中国共产党   1篇
中国政治   24篇
政治理论   144篇
综合类   8篇
  2023年   10篇
  2022年   4篇
  2021年   7篇
  2020年   17篇
  2019年   29篇
  2018年   27篇
  2017年   38篇
  2016年   31篇
  2015年   23篇
  2014年   25篇
  2013年   89篇
  2012年   46篇
  2011年   25篇
  2010年   27篇
  2009年   29篇
  2008年   22篇
  2007年   35篇
  2006年   26篇
  2005年   23篇
  2004年   21篇
  2003年   19篇
  2002年   16篇
  2001年   17篇
  2000年   11篇
  1999年   10篇
  1998年   5篇
  1997年   10篇
  1996年   4篇
  1995年   2篇
  1994年   10篇
  1993年   2篇
  1992年   6篇
  1991年   3篇
  1990年   13篇
  1989年   3篇
  1988年   9篇
  1987年   5篇
  1986年   5篇
  1985年   4篇
  1984年   7篇
  1983年   8篇
  1982年   4篇
  1981年   5篇
  1979年   6篇
  1978年   2篇
  1977年   3篇
  1976年   2篇
  1975年   4篇
  1974年   2篇
  1968年   2篇
排序方式: 共有757条查询结果,搜索用时 31 毫秒
201.
Ethanol formation in unadulterated postmortem tissues   总被引:2,自引:0,他引:2  
During the investigation of aviation accidents, postmortem samples obtained from fatal accident victims are submitted to the FAA's Civil Aerospace Medical Institute (CAMI) for toxicological analysis. During toxicological evaluations, ethanol analysis is performed on all cases. Many species of bacteria, yeast, and fungi have the ability to produce ethanol and other volatile organic compounds in postmortem specimens. The potential for postmortem ethanol formation complicates the interpretation of ethanol-positive results from accident victims. Therefore, the prevention of ethanol formation at all steps following specimen collection is a priority. Sodium fluoride is the most commonly used preservative for postmortem specimens. Several studies have been published detailing the effectiveness of sodium fluoride for the prevention of ethanol formation in blood and urine specimens; however, our laboratory receives blood or urine in approximately 70% of cases. Thus, we frequently rely on tissue specimens for ethanol analysis. The postmortem tissue specimens received by our laboratory have generally been subjected to severe trauma and may have been exposed to numerous microbial species capable of ethanol production. With this in mind, we designed an experiment utilizing unadulterated tissue specimens obtained from aviation accident victims to determine the effectiveness of sodium fluoride at various storage temperatures for the prevention of microbial ethanol formation. We found that without preservative, specimens stored at 4 degrees C for 96 h showed an increase in ethanol concentration ranging from 22 to 75 mg/hg (average 42 +/- 15 mg/hg). At 25 degrees C, these same specimens showed an increase ranging from 19 to 84 mg/hg (average 45 +/- 22 mg/hg). With the addition of 1.00% sodium fluoride, there was no significant increase in ethanol concentration at either temperature.  相似文献   
202.
Voluntary environmental programs (VEPs) have become a popular alternative to traditional regulation. However, little is known about whether these programs are sending accurate signals about the environmental practices of their participants. As a means for understanding signaling accuracy, this research investigates VEP design characteristics. The findings suggest that there are four distinct types of programs with varying degrees of rigor. Because information for differentiating among program types is limited, less rigorous VEPs can signal that their administrative, environmental performance and conformance requirements are comparable to programs with more robust designs. Further, the lack of monitoring and sanctions in less rigorous programs create opportunities for participants to free-ride and receive benefits without satisfying VEP requirements. Unless some means of distinguishing among program types is implemented, these issues can threaten the long term viability of VEPs as a tool for environmental protection, and the credibility of market mechanisms more broadly.  相似文献   
203.
204.
In this study we used the theory of economic regulation and public choice to derive a model to explain the pattern of public sector bargaining laws among the states. We find this type of legislation is influenced by the following demand factors: (1) the extent of public sector union membership, which represents the interest group hypothesis, has a positive influence on pro-union legislation; (2) the extent of employer opposition to unions, as measured by unfair labor practice charges against employers in representation elections, has a negative effect on bargaining laws; (3) two taste variables — the salaries of public employees and the percent of nonwhite employment in the state — have a positive influence on these laws. A result which will be surprising to many people is that the extent of private sector union membership has no significant influence on the passage of public sector bargaining legislation.Our empirical analysis indicates that supply factors are also important in explaining the pattern of public employee bargaining laws across the state. We find that states are more likely to enact pro-union legislation under the following conditions: (1) constituents appear to hold pro-labor views as represented by their Congressmen's voting record; (2) neighboring states have passed mandatory bargaining laws; and (3) when competition is greater among the political parties.  相似文献   
205.
In 1972 the United States Supreme Court in Furman V. Georgia found that the death penalty as it was then being applied was cruel and unusual punishment in violation of the Eighth and Fourteenth Amendments of the United States Constitution. Furman provided few constitutional guidelines, but states reinacted their death penalty statutes.In 1976 the Court began to receive appeals from death sentences imposed under the reinacted statutes. In its decisions the Court began to establish guidelines. It found the death penalty was not per se cruel and unusual punishment. Before the death penalty can be imposed the court must take into consideration any mitigating circumstances and the case must be reviewed by the state supreme court. A mandatory death sentence is unconstitutional.Other issues including proportionality, due process and finality of judgment will be examined in the next segment of this study.  相似文献   
206.
The role of the public in US policy making has shifted substantially during the past several decades. This shift is particularly evident in environmental policy, where collaboration among multiple stakeholders is on the rise. Much of the literature on collaborative environmental management emphasizes the need for widespread community involvement, especially from private citizens. Many proponents of collaboration have argued that broad inclusion can lead to better environmental solutions while also establishing legitimacy, building social capital, and overcoming conflicts. Yet such broad inclusion may be costly in terms of time, energy, and resources, and it may not yield the desired results. Thus, a key question is how the breadth of public involvement is linked to collaborative group accomplishments. This study, using watershed groups in Ohio, demonstrates several links between group membership and results. Groups with a broader array of participants tend to excel in watershed plan creation, identifying/prioritizing issues, and group development and maintenance. In addition, groups comprised of a relatively balanced mix of governmental and non-governmental participants are more likely to list planning/research and group development and maintenance results than are groups comprised primarily of non-governmental participants. In contrast, groups with a narrower membership and groups that are composed primarily of non-governmental participants may focus more on pressuring government for policy change.  相似文献   
207.
Moore M 《Time》2007,169(22):48-50
  相似文献   
208.
209.
Our article explores the contribution of local initiatives to the creation of path dependencies for energy transition in Germany and Japan in the face of resistance from entrenched incumbents at the national level. We use a process‐tracing methodology based partly on interviews with local participants. In particular, we explore the role of local initiatives in securing “socio‐political space” for the expansion of renewable energy (RE) and in embedding themselves in “ecosystems” of public and private institutions. German energy activists were more successful than their Japanese counterparts in expanding this space and creating positive feedback in part because they were able to build horizontal networks that anchored the energy transition firmly in local communities. Although problems with grid technology have led to retrenchment in both cases, Japanese activists' reliance on vertical networks has limited their ability to weather a backlash from national government and utility actors. Our study demonstrates the interaction of political, economic/technological, and legitimation paths to energy transition and highlights the importance of the latter two.  相似文献   
210.
Abstract

A discrete choice experiment was conducted to discover the relative importance of five characteristics of developing countries considered by people when choosing countries to donate money to. The experiment was administered via an online survey involving almost 700 university student participants (potential donors). The most important recipient country characteristic for participants on average is hunger and malnutrition, followed by child mortality, quality of infrastructure, income per capita, and, least importantly, ties to the donor’s home country. A cluster analysis of participants’ individual ‘part worth utilities’ representing the relative importance of the country characteristics reveals they are not strongly correlated with participants’ demographic characteristics.  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