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   1064篇
  免费   64篇
各国政治   57篇
工人农民   152篇
世界政治   102篇
外交国际关系   56篇
法律   531篇
中国政治   15篇
政治理论   212篇
综合类   3篇
  2024年   2篇
  2023年   18篇
  2022年   9篇
  2021年   14篇
  2020年   30篇
  2019年   54篇
  2018年   66篇
  2017年   85篇
  2016年   78篇
  2015年   42篇
  2014年   50篇
  2013年   152篇
  2012年   56篇
  2011年   59篇
  2010年   34篇
  2009年   47篇
  2008年   48篇
  2007年   53篇
  2006年   50篇
  2005年   30篇
  2004年   17篇
  2003年   14篇
  2002年   15篇
  2001年   8篇
  2000年   5篇
  1999年   10篇
  1998年   7篇
  1997年   6篇
  1996年   4篇
  1995年   8篇
  1994年   5篇
  1993年   6篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1982年   4篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1974年   2篇
  1968年   1篇
排序方式: 共有1128条查询结果,搜索用时 15 毫秒
251.
Social impact bonds, known as pay‐for‐success (PFS) initiatives in the United States, have attracted attention as a novel strategy for financing and providing preventive services to the most vulnerable populations. This article provides an exploratory qualitative analysis of the Preschool PFS Feasibility Pilot grant applications and projects initiated by the U.S. Department of Education to encourage state and local exploration of PFS for implementing high‐quality preschool programs. Drawing on the public administration evidence base that informs PFS design, the authors examine the feasibility pilots’ features and investigate why grant applicants saw PFS as a promising strategy for achieving their preschool program goals. The challenges encountered, lessons learned, and perceived viability of fully executed PFS preschool programs are also discussed. Findings show that few projects are advancing toward formal PFS arrangements, with many struggling to overcome constrained capacities, structural and political barriers, and inherent incentives to minimize risk and loss.  相似文献   
252.
Abstract: Few techniques offer “in situ” methods of friction ridge skin mark development. “In situ” development reduces mark transportation, degradation, and often cost. The effectiveness of cyanoacrylate fuming using the SUPERfume® and dusting with aluminum powder for latent fingermark development on several nonporous surfaces, stored in various temperature environments for time periods up to 52 weeks, was investigated. Five thousand and four hundred latent fingermarks were deposited under controlled conditions and graded. The results suggested that cyanoacrylate fuming (SUPERfume®, Foster and Freeman, U.K.) was more effective at developing latent fingermarks on textured and smooth plastic surfaces and for marks stored in temperatures of 37°C, whereas aluminum powder was more effective on glass, enameled metal paint, and varnished wood, and for storage temperatures below 20°C. There were no significant benefits to using either technique for marks older than 24 h, but it was possible to develop fingermarks following 52 weeks of storage using both techniques.  相似文献   
253.
Little is known about the decomposition of remains in aquatic environments of varying pH, and even less is known about the specific effects of these environments on bone. Bovine bones were placed in solutions of pH 1, 4, 7, 10, and 14 and observed over a period of 1 year. All solutions eventually removed or dissolved the soft tissues from the external surface of the bone. The pH 7 and pH 10 solutions had little effect on the bone, but the other solutions affected the bone to varying degrees. Extreme pH levels were the most destructive, while more moderate pH levels had lesser but significant and interesting effects. Empirical data on postmortem aquatic changes may be extremely useful in forensic contexts for both improving time since death estimates and also for providing better information to underwater recovery experts thereby potentially increasing the quantity and quality of remains recovery.  相似文献   
254.
One year after passage, the Patient Protection and Affordable Care Act (ACA) remains a divisive topic. Most publicly released polls on the law have focused on the views of Americans as a whole. But with much of the responsibility of implementation lying with the states, this essay explores whether opinion differs geographically. The analysis finds that views on the health reform law do differ by region, and these differences are most likely driven by the political leanings of a given area. While opinion nationally differs by age and race, this pattern does not hold when looking by region. Areas that have a larger share of uninsured and are slated to receive greater federal funding under the ACA also do not differ in their opinions. These data suggest that regional variations in attitudes about the ACA are based less on the demographic structure of a region and more on the political ideologies of residents in a given region. As implementation of the law continues, this analysis shows that national opinion data mask important regional variations in views of the ACA.  相似文献   
255.
Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases.  相似文献   
256.
Forensic entomotoxicology studies the usefulness of insects as alternative toxicological samples. Use of insects as alternative matrix for drug detection is well documented and recommended when conventional matrices such as blood, urine or internal organs are no longer available. However, several limitations of entomotoxicology have been highlighted, especially concerning interpretation of the drug concentrations in insects on human forensic cases. In addition, the lack of knowledge in pharmacokinetic of drugs in insects, large variability of experimental set-up and toxicological analysis compromise the utility of this science. This review focuses on the current knowledge of factors influencing drug detection in insects. Reasons for the current limitations, but also recommendations for future research are discussed and proposed in this paper.  相似文献   
257.
258.
This study investigated childhood physical abuse and ulcers in a regionally representative community sample. Age, race and sex were controlled for in addition to five clusters of potentially confounding factors: adverse childhood conditions, adult socioeconomic status, current health behaviors, current stress and marital status, and history of mood/anxiety disorders. Childhood physical abuse is associated with many negative physical and psychological adult health outcomes. Two recent studies demonstrate a potential link between childhood physical abuse and peptic ulcer disease in adulthood. The authors use regional data for the Canadian provinces of Manitoba and Saskatchewan from the 2005 Canadian Community Health Survey. Of the 13,069 respondents with complete data on abuse and ulcers, 7.3% (n = 1,020) report that they had been physically abused as a child by someone close to them and 3.0% (n = 493) report that they had been diagnosed with peptic ulcers by a health professional. The regional response rate is approximately 84%. Findings show that those reporting abuse had more than twice the prevalence of ulcers than did those not reporting abuse (6.6% vs. 2.7%). The fully adjusted odd ratio of peptic ulcers among those who had reported childhood physical abuse is 1.68 (95% CI = 1.22, 2.32). A significant and stable relationship between childhood physical abuse and peptic ulcers is found, even when taking into account five clusters of potentially confounding factors. Prospective studies that apply the biopsychosocial model are likely to be the most effective for identifying the pathways that connect childhood physical abuse and ulcer disease.  相似文献   
259.
Tharp AT  DeGue S  Lang K  Valle LA  Massetti G  Holt M  Matjasko J 《Journal of interpersonal violence》2011,26(16):3383-92; author reply 3393-402
Foubert, Godin, and Tatum describe qualitative effects among college men of The Men's Program, a one-session sexual violence prevention program. This article and the program it describes are representative of many sexual violence prevention programs that are in practice and provide an opportunity for a brief discussion of the development and evaluation of sexual violence prevention approaches. In this commentary, we will focus on two considerations for an evolving field: the adherence to the principles of prevention and the use of rigorous evaluation methods to demonstrate effectiveness. We argue that the problem of sexual violence has created urgency for effective prevention programs and that scientific and prevention standards provide the best foundation to meet this need.  相似文献   
260.
Fetal alcohol spectrum disorder can occur in children when a mother consumes alcohol while pregnant. It can manifest in a range of both physical and mental impairments and in varying degrees of seriousness. The act of consuming alcohol while pregnant arguably constitutes a breach of the duty of care that a mother owes to her unborn child and may lead to an award of damages for children with the disorder. However, to conclude that a duty is owed to an unborn child may be legally problematic. Further, an award of compensation may be of little utility to the child. It is therefore suggested that intervention strategies should instead be implemented which target relevant population groups and which prevent and assist in the management of the disorder.  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