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   69377篇
  免费   3325篇
  国内免费   2篇
各国政治   4501篇
工人农民   2852篇
世界政治   5971篇
外交国际关系   3953篇
法律   31630篇
中国共产党   193篇
中国政治   1344篇
政治理论   20734篇
综合类   1526篇
  2021年   484篇
  2020年   1206篇
  2019年   1531篇
  2018年   1683篇
  2017年   1984篇
  2016年   2164篇
  2015年   1870篇
  2014年   2143篇
  2013年   10592篇
  2012年   1644篇
  2011年   1791篇
  2010年   1984篇
  2009年   2232篇
  2008年   1871篇
  2007年   1869篇
  2006年   2063篇
  2005年   1933篇
  2004年   1711篇
  2003年   1509篇
  2002年   1578篇
  2001年   1593篇
  2000年   1344篇
  1999年   1220篇
  1998年   1090篇
  1997年   971篇
  1996年   944篇
  1995年   909篇
  1994年   916篇
  1993年   940篇
  1992年   933篇
  1991年   960篇
  1990年   918篇
  1989年   970篇
  1988年   932篇
  1987年   970篇
  1986年   913篇
  1985年   1017篇
  1984年   904篇
  1983年   956篇
  1982年   886篇
  1981年   827篇
  1980年   648篇
  1979年   681篇
  1978年   595篇
  1977年   522篇
  1976年   483篇
  1975年   403篇
  1974年   408篇
  1973年   419篇
  1972年   364篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
251.
实验室条件下长角血蜱甘肃株孤雌生殖种群的生物学特性   总被引:1,自引:0,他引:1  
在实验室条件下,对我国北方长角血蜱甘肃株孤雌生殖种群的生活史进行了首次观察。研究发现,行孤雌生殖的长角血蜱为三宿主蜱;在兔体完成1个世代共需106~154 d,饥饿期的幼蜱、若蜱与两性生殖的饥饿幼蜱、若蜱体重的差异不显著(P>0.05),而饱血体重与两性生殖的长角血蜱种群饱血体重差异极显著(P<0.01);雌蜱饱血体重可达吸血前的108.46±19.72倍,与两性生殖的种群饱血体重差异亦极显著(P<0.01)。雌蜱产卵量与饱食体重之间呈极显著正相关r=0.897 0(P<0.01);生殖效率指数REI=6.76,生殖适合度指数RFI=6.29;蜱发育时间在不同季节无明显变化。  相似文献   
252.
顶空固相微萃取气相色谱法快速检测尿液中氯胺酮   总被引:1,自引:1,他引:0  
目的建立快速检测吸毒人员尿液中氯胺酮的顶空固相微萃取(HS/SPME)-GC/NPD的方法。方法样品瓶中加入尿液、氢氧化钠溶液、氯化钠,在95℃下加热搅拌,用聚二甲基硅氧烷SPME萃取头(100μm)顶空萃取20min,气相色谱氮磷检测器检测,外标法定量。结果尿液中氯胺酮浓度在0.2~20.0μg/ml范围内呈现线性关系(r2=0.9965),尿液添加1.0μg氯胺酮,平均回收率102.6%,RSD=3.39%(n=7),检测限1.13ng/ml(S/N=3)。结论建立的方法简单、快速、灵敏、准确,十分适合尿液等生物检材中氯胺酮的快速定性定量分析。  相似文献   
253.
254.
255.
256.
The main aim of this paper is to advance knowledge and (especially) theories about developmental and life‐course criminology (DLC). First, I review the widely accepted DLC findings that all DLC theories have been designed to explain. Second, I review more contentious and unresolved empirical DLC issues that might present challenges to DLC theories. Third, I describe my own DLC theory and specify how it addresses key empirical and theoretical questions. Fourth, I summarize five important DLC theories, by Catalano and Hawkins, Sampson and Laub, Moffitt, LeBlanc, and Thornberry and Krohn. Fifth, I identify differences in assumptions and predictions between my theory and the other five theories. Finally, I recommend a detailed comparison of the key features of all DLC theories, of their answers to key empirical and theoretical questions, and of their predictions regarding key unresolved empirical DLC issues.  相似文献   
257.
Research has indicated that school factors such as communal school organization and student bonding are predictive of school disorder, with greater communal organization and greater student bonding leading to less delinquency and victimization. Data from a nationally representative sample of 254 public, nonalternative, secondary schools were used to examine structural equation models representing hypothesized relationships among communal school organization, student bonding, and school disorder. The hypothesis that communally organized schools would have less disorder held true for teacher victimization and student delinquency, but not for student victimization. In addition, the hypothesis that the relationship between communal school organization and school disorder would be mediated by student bonding was supported for student delinquency, but not for teacher victimization.  相似文献   
258.
“Discretion” holds an unrivaled position at the core of the notional inventory employed in the study of criminal justice generally and policing particularly. Efforts to systematically define the term have been irregular and its status in the empirical literature is an ambiguous one. While spoken of as a quantitative aspect of the policing which influences behavior, measurement is rarely addressed. After sketching problems in present formulations, discretion is recast in terms of perceived job autonomy and an outline of two general constructs is contributed in hopes of renewing consideration of the potential relevance of the concept for police theory and research.  相似文献   
259.
To demonstrate that norms have independent causal power, constructivists de-emphasise material factors related to state interests and highlight social factors. Similarly, they conceptualise international organisations as autonomous from state influence, and focus on cases featuring non-state actors that stimulate a “tipping point” of norm diffusion among states in advance of state sponsorship. By contrast, this article utilises an historical materialist approach that admits both social and material data to examine the contrasting case of population control. It finds that US corporate foundations, eugenist demographers, feminist birth control activists and related NGOs conceptualised and promoted population control in the United States, at the United Nations, and across developing countries. However, the tipping point of norm diffusion occurred only after the United States publicly advocated population control. Indeed, material and social factors were inextricably bound together.  相似文献   
260.
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