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   1854篇
  免费   54篇
各国政治   102篇
工人农民   65篇
世界政治   175篇
外交国际关系   124篇
法律   748篇
中国政治   18篇
政治理论   627篇
综合类   49篇
  2023年   8篇
  2020年   26篇
  2019年   33篇
  2018年   31篇
  2017年   43篇
  2016年   48篇
  2015年   36篇
  2014年   35篇
  2013年   334篇
  2012年   52篇
  2011年   41篇
  2010年   39篇
  2009年   48篇
  2008年   67篇
  2007年   50篇
  2006年   62篇
  2005年   58篇
  2004年   57篇
  2003年   54篇
  2002年   48篇
  2001年   39篇
  2000年   37篇
  1999年   33篇
  1998年   43篇
  1997年   32篇
  1996年   26篇
  1995年   34篇
  1994年   22篇
  1993年   31篇
  1992年   24篇
  1991年   19篇
  1990年   27篇
  1989年   34篇
  1988年   34篇
  1987年   31篇
  1986年   20篇
  1985年   29篇
  1984年   26篇
  1983年   26篇
  1982年   20篇
  1981年   15篇
  1980年   17篇
  1979年   9篇
  1978年   11篇
  1977年   12篇
  1976年   7篇
  1975年   10篇
  1973年   10篇
  1972年   10篇
  1969年   7篇
排序方式: 共有1908条查询结果,搜索用时 15 毫秒
271.
The discrimination of noncolored transparent polyethylene bags was studied by several nondestructive and semidestructive analytical methods. X-ray diffraction, infrared spectroscopy, and optical microscopy (differential interference contrast microscopy and phase contrast microscopy) were applied to polyethylene films. X-ray diffraction was used to distinguish variations in the crystalline phase, infrared spectroscopy was used to distinguish variations in the molecular components, and optical microscopy was used to distinguish the different surface morphologies. The results show that X-ray diffraction classifies the crystalline phase of the film depending on whether it is made from low-density polyethylene, linear low-density polyethylene, or high-density polyethylene; that infrared spectroscopy is useful to distinguish the molecular components and it is the most discriminating technique; and that optical microscopy discriminate films easily by their morphological differences.  相似文献   
272.
Faced with a choice between John McCain and Barack Obama, voters in 2008 were swayed by the familiar play of factors—party identification, policy preferences, and economic conditions—but also, we find, by ethnocentrism, a deep‐seated psychological predisposition that partitions the world into ingroups and outgroups—into “us” and “them.” The effect of ethnocentrism was significant and substantial, and it appeared over and above the effects due to partisanship, economic conditions, policy stances, political engagement, and several varieties of conservatism. Two features of Obama were primarily responsible for triggering ethnocentrism in 2008: his race and his imagined Muslim faith. As such, we demonstrate that ethnocentrism was much more important in 2008 than in the four presidential elections immediately preceding 2008, and we show that it was much more important in the actual contest between Senator McCain and Senator Obama than in a hypothetical contest between Senator McCain and Senator Clinton.  相似文献   
273.
Cognitive biases are heuristics that shape individual preferences and decisions in a way that is at odds with means‐end rationality. The effects of cognitive biases on governing are underexplored. The authors study how election administrators’ cognitive biases shape their preferences for e‐voting technology using data from a national survey of local election officials. The technology acceptance model, which employs a rational, means‐end perspective, suggests that the perceived benefits of e‐voting machines explain their popularity. But findings indicate that cognitive biases also play a role, even after controlling for the perceived benefits and costs of the technology. The findings point to a novel cognitive bias that is of particular interest to research on e‐government: officials who have a general faith in technology are attracted to more innovative alternatives. The authors also find that local election officials who prefer e‐voting machines do so in part because they overvalue the technology they already possess and because they are overly confident in their own judgment.  相似文献   
274.
Information exchange in policy networks is usually attributed to preference similarity, influence reputation, social trust, and institutional actor roles. We suggest that political opportunity structures and transaction costs play another crucial role and estimate a rich statistical network model on tie formation in the German toxic chemicals policy domain. The results indicate that the effect of preference similarity is absorbed by institutional, relational, and social opportunity structures. Political actors choose contacts who minimize transaction costs while maximizing outreach and information. We also find that different types of information exchange operate in complementary, but not necessarily congruent, ways.  相似文献   
275.
Prolapse rectum (PR) or protrusion of the rectum beyond the anus occurs frequently in populations at both extremes of age. In the pediatric population, in developed countries, the commonest cause for PR is thought to be cystic fibrosis (CF). Treatment options for CF include conservative management, surgical resection and fixation, suturing, and injection sclerotherapy (IS). The last is considered an attractive treatment option because it is minimally invasive. In this case report, the authors present the details about a 2-year-old female child, with PR and CF, who died after IS, using phenol as the sclerotherapeutic agent. Autopsy findings and toxicology tests performed to establish phenol toxicity are documented. The available literature is reviewed. This case report underscores the risks of using phenol for IS and emphasizes the point that the procedure is not innocuous and an adverse outcome including fatality is a possibility.  相似文献   
276.
One of the greatest challenges to any Court is to determine the truth in the face of often conflicting evidence. In both the Civil and Criminal Courts, cases stand or fall on what the trier of fact determines is true. In civil cases, this is often a Judge sitting alone, whereas in criminal matters the tribunal of fact is usually a jury. The standard of proof required in criminal cases is ??beyond reasonable doubt??. Juries are directed that they can only convict ??if they are sure??. The jurors might be sure, but are they correct? There now exists a substantial body of scientific evidence, which indicates that humans are very poor lie detectors. In fact, in some experiments even experienced police officers perform only just above chance. Given this inherent flaw in the system, is it not time to re-evaluate how cases are put before the Courts, and what weight is put on oral testimony.  相似文献   
277.
This article describes the use of an anti-Stokes luminescent material (upconverter), yttrium vanadate doped with ytterbium and erbium (YVO(4):Er,Yb), for the development of latent fingermarks on a range of non-porous surfaces. Anti-Stokes luminescent materials emit light at shorter wavelengths than the excitation wavelength. This property is unusual in both natural and artificial materials commonly found as exhibits in forensic science casework. As a result, fingermark detection techniques based on anti-Stokes luminescence are potentially extremely sensitive and selective. Latent fingermarks on non-luminescent and inherently luminescent substrates, including Australian polymer banknotes (a well-known 'difficult' surface), were developed with YVO(4):Er,Yb by dry powder and wet powder techniques. The effectiveness of YVO(4):Er,Yb for fingermark detection was compared with that of cyanoacrylate fuming and of sodium yttrium tetrafluoride doped with ytterbium and erbium (NaYF(4):Er,Yb). The results illustrate some benefit of luminescent up-converting phosphors over traditional luminescence techniques for the detection of latent fingermarks.  相似文献   
278.
Child sexual abuse (CSA) often requires psychological treatment to address the symptoms of victim trauma. Barriers to entry and completion of counseling services can compromise long-term well-being. An integrated medical and mental health evaluation and treatment model of a child advocacy center (CAC) has the potential to reduce barriers to mental health treatment. Objective: (a) to describe characteristics between CSA patients who engage versus those who do not engage in mental health treatment and (b) to identify factors associated with successful completion of mental health treatment goals. For design/setting, a retrospective cohort study was conducted of CSA patients (ages 3-16 years) referred to mental health services following a CAC assessment. Outcome variables included linkage with treatment and completion of treatment. Independent variables included demographics, abuse characteristics, and therapist characteristics. Data were abstracted from the CAC and billing databases. Results: Four hundred ninety subjects were evaluated. Subjects were as follows: predominately female (74%), White (60%), and more than half received Medicaid (56%). Mean age was 8.4 years. About 52% linked with mental health services and 39% of patients that successfully linked with mental health services completed therapy. Successful linkage was independently associated with referrals to other counseling services (AOR 8.4 [2.5, 27.7]). Successful completion of therapy was independently associated with caregiver participation in therapy (AOR 3.2 [1.8, 6.0]) and if the patient was referred to other counseling services (AOR 4.1 [1.9, 8.5]). There were no differences between subjects that linked and/or completed therapy and those that did not with regard to demographic characteristics or abuse severity. Conclusion: In contrast to previous reports, efforts at our CAC seem to overcome linkage barriers in this population. However, there remain challenges in achieving successful completion of treatment goals in this population. Engaging caregivers' involvement in therapy services had a positive effect with successfully achieving treatment goals.  相似文献   
279.
This article examines a training approach for community health volunteers which increased access to maternal health services in rural communities in Zambia. The effectiveness of the training approach was evaluated in an operations research component. Skilled birth attendance rates increased by 63% from baseline over a two-year period in the intervention districts, out-performing increases recorded in control sites at statistically significant levels. As a low-cost, high-impact intervention which shows good sustainability potential, the approach is suitable for national level scale-up and for adaptation for use in other countries in support of maternal and new-born health goals.  相似文献   
280.
An algorithm incorporating multidetector computed tomography (MDCT), digital radiographs, and external examination was used to triage cases for noninvasive or complete autopsy after a natural disaster. The algorithm was applied to 27 individuals who died during or soon after the earthquake that struck the Republic of Haiti on January 12, 2010. Of the 27 cases reviewed, 7 (26%) required a complete autopsy to determine cause and manner of death. In the remaining 20 (74%), cause and manner of death were determined with a reasonable degree of medical certainty after review of circumstances, an external examination, and postmortem imaging by MDCT and digital radiography (noninvasive autopsy). MDCT was particularly useful in detecting skeletal fractures caused by blunt force injury which were not evident on digital radiographs. The algorithm incorporating postmortem MDCT can be useful in the triage of human remains for autopsy after a natural disaster.  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