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   260篇
  免费   17篇
各国政治   17篇
工人农民   17篇
世界政治   61篇
外交国际关系   19篇
法律   121篇
政治理论   42篇
  2023年   2篇
  2022年   2篇
  2021年   4篇
  2020年   7篇
  2019年   10篇
  2018年   10篇
  2017年   13篇
  2016年   5篇
  2015年   7篇
  2014年   9篇
  2013年   34篇
  2012年   11篇
  2011年   13篇
  2010年   6篇
  2009年   5篇
  2008年   17篇
  2007年   14篇
  2006年   11篇
  2005年   24篇
  2004年   10篇
  2003年   14篇
  2002年   15篇
  2000年   2篇
  1999年   1篇
  1998年   5篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   4篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
排序方式: 共有277条查询结果,搜索用时 278 毫秒
111.
Policy makers have identified the non-discrimination principle as a key instrument to regulate vertically integrated firms in control of upstream bottlenecks. It has been argued that the non-discrimination principle may create a level playing field, but at the expense of higher consumer prices. However, this rests on the assumption that the firms do not respond strategically to the regulation. We show that a non-discrimination requirement makes the vertically integrated firm behave more aggressively. Consequently, non-discrimination regulation rarely creates a level playing field. Neither does it necessarily increase end-user prices. Indeed, we show that end-user prices may fall.   相似文献   
112.
113.
114.
One hundred and fifty-five cord cells were tested for the red blood cell antigens Lua, Lub and Cob in order to collect data on the early postnatal expression of these markers. Additionally, dosage studies were carried out in 8–10-month-old heterozygous children. Antigens Lua and Lub revealed to be significantly less expressed in children of both ages compared with those of their mothers, whereas no such differences could be demonstrated in the expression of the antigen Cob.  相似文献   
115.
The resilience of autocratic regimes in various world regions and the emerging model of illiberal capitalist autocracies (China, Russia) have led scholars to shift their attention to the durability of such regimes. Autocracies not only resist the global spread of democracy, but are developing their own domestic efforts in the promotion of autocracy. This study argues that processes at the regional level aim at the dissemination and diffusion of autocratic norms, structures, processes, policy approaches or practices. Likewise, we propose that authoritarian gravity centres can be attributed with both the active promotion of autocracy as well as the inducement of diffusion effects. Our research tries to shed some light on their strategies and modes of influence on countries in their geopolitical proximity (target states).  相似文献   
116.
Aminoindanes are a class of novel psychoactive substances (NPSs) that have become more prevalent over the past decade. GC–MS is often utilized for identifying seized drugs and is well regarded for its ability to separate mixtures. However, certain aminoindanes have similar mass spectral data and require specific gas chromatographic stationary phases for separation. Derivatization is an alternative method that can be applied to GC–MS to enhance chromatographic results, providing more selective analysis in seized-drug identification. This study investigates derivatization techniques to provide options for forensic science laboratories in accurately identifying aminoindanes. Three derivatization reagents, N-methyl-bis(trifluoroacetamide) (MBTFA), heptafluorobutyric anhydride (HFBA), and ethyl chloroformate (ECF) were evaluated for the analysis of eight aminoindanes by GC–MS using two common gas chromatographic stationary phases, Rxi®-5Sil MS and Rxi®-1Sil MS. All three derivatization methods successfully isolated eight aminoindanes, including the isomers 4,5-methylenedioxy-2-aminoindane (4,5-MDAI), and 5,6-methylenedioxy-2-aminoindane (5,6-MDAI) that could not be differentiated prior to derivatization. Reduced peak tailing and increased abundance were observed after derivatization for all the compounds, and mass spectra of the derivatives contained individualizing fragment ions that allowed for further characterization of the aminoindanes. This excluded 4,5-MDAI and 5,6-MDAI as they shared the same characteristic ions and were only distinguishable by their retention times. All three derivatization techniques used in this study allow for successful characterization of the aminoindanes and give forensic science laboratories flexibility in their analysis approach when they encounter these compounds.  相似文献   
117.

Though reasonable people may argue about whether cable television and local telephone services are natural monopolies in theory, historically they have developed with infrastructures that make them more likely to have important declining cost characteristics in reality. Additionally, common carriage issues, especially for telephones, may necessitate regulatory oversight. Though touted as deregulation, and certainly eliminating many cross‐industry barriers, the Telecommunications Act of 1996 is better understood as reregulation. The act maintains a common carriage philosophy while attempting to promote competition. However, evidence indicates it is unlikely that the new regulatory regime will result in efficient prices or true competition. Instead, duopoly in cable and oligopoly in telephony are probably the best that can be achieved under the act.  相似文献   
118.
Abstract

Significant differences between subgroups of juvenile sex offenders (JSOs) are found in both Dutch and international research. Most of this literature represents the more delinquent and more disturbed sections of the population of JSOs. This paper describes the characteristics of 302 less disturbed and less violent JSOs in a mandatory educational programme. Characteristics of exhibitionists (n=26), child molesters (n=39) and peer offenders (n=237) are compared. Peer offenders are subdivided into solo offenders (n=90) and group offenders (n=142). Variables are: demographics, family background, psychosocial functioning, offence characteristics and victim characteristics. Significant differences are found in a large number of variables, supporting findings from earlier research in clinical samples. Differences between subgroups are largest between group-offending peer offenders, on one hand, and exhibitionists and child molesters on the other hand. The majority of our sample seems to have an ordinary background and shows no apparent sign of psychosocial dysfunction. The clinical and theoretical relevance of the results is discussed.  相似文献   
119.
120.
Although cognitive rumination is related to violence perpetration, not all people who ruminate become violent. Four personality variables—impulsivity, anxiety, anger-in, anger-out—were tested as possible moderators of the link between the tendency to ruminate and the frequency of intimate partner violence (IPV). Variables related to the Behavioral Activation System (anger-out and impulsivity) were predicted to strengthen the rumination-IPV link; whereas measures related to the Behavioral Inhibition System (anger-in and anxiety) would suppress this link. As predicted, anger-out, anger-in, and impulsivity moderated the relation between rumination and IPV. No evidence was found for suppressor variables. Thus, appetitive drives appear to amplify the effect of rumination on violence. Clinically, therapeutic techniques that address rumination, anger, and impulsivity may help to reduce IPV risk.  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