全文获取类型
收费全文 | 7390篇 |
免费 | 175篇 |
专业分类
各国政治 | 470篇 |
工人农民 | 316篇 |
世界政治 | 487篇 |
外交国际关系 | 282篇 |
法律 | 4502篇 |
中国政治 | 42篇 |
政治理论 | 1415篇 |
综合类 | 51篇 |
出版年
2020年 | 83篇 |
2019年 | 105篇 |
2018年 | 138篇 |
2017年 | 154篇 |
2016年 | 160篇 |
2015年 | 117篇 |
2014年 | 145篇 |
2013年 | 818篇 |
2012年 | 160篇 |
2011年 | 162篇 |
2010年 | 153篇 |
2009年 | 158篇 |
2008年 | 191篇 |
2007年 | 194篇 |
2006年 | 192篇 |
2005年 | 153篇 |
2004年 | 146篇 |
2003年 | 165篇 |
2002年 | 134篇 |
2001年 | 278篇 |
2000年 | 234篇 |
1999年 | 224篇 |
1998年 | 96篇 |
1997年 | 78篇 |
1996年 | 73篇 |
1995年 | 65篇 |
1994年 | 74篇 |
1993年 | 68篇 |
1992年 | 121篇 |
1991年 | 159篇 |
1990年 | 154篇 |
1989年 | 142篇 |
1988年 | 148篇 |
1987年 | 165篇 |
1986年 | 159篇 |
1985年 | 149篇 |
1984年 | 131篇 |
1983年 | 120篇 |
1982年 | 81篇 |
1981年 | 92篇 |
1980年 | 68篇 |
1979年 | 126篇 |
1978年 | 86篇 |
1977年 | 72篇 |
1976年 | 56篇 |
1975年 | 82篇 |
1974年 | 87篇 |
1973年 | 82篇 |
1972年 | 56篇 |
1971年 | 57篇 |
排序方式: 共有7565条查询结果,搜索用时 93 毫秒
241.
John Kerbs Ph.D. Kyubeom Choi Ph.D. Stephen Rollin Ed.D. Robert Gutierrez Ed.D. Isabelle Potts J.D. Jayme Harpring Ph.D. Alia H. Creason Ph.D. Tam Dao M.S. 《American Journal of Criminal Justice》2005,30(1):121-141
Although past research has developed scales for the incidence, prevalence, and fear of student-on-student victimization (SSV),
little is known about the scaling of perceived risk (i.e., the cognitive appraisal of the chances of experiencing SSV). Hence,
this study examined self-report survey data for the perceived risk of SSV as measured in the Adolescent Index for School Safety
(AISS). Children in grades 7 through 10 (n=337) in a single Florida public school completed the AISS. Factor analyses using
Maximum Likelihood Estimation with Oblimin Rotation identified nine unique factors for perceived risk. Reliability analyses
found standardized Cronbach Alphas that ranged from .64 to .91, and seven out of the nine identified scales were above .80,
which suggested good to excellent internal consistency. Future research should examine the content validity, construct validity,
and predictive validity for the AISS and other self-report surveys of SSV dynamics.
This publication was made possible by a grant [#97-MU-FX-KO12 (S-l)] from the Office of Juvenile Justice and Delinquency Prevention
(O.J.J.D.P.), United States Department of Justice (U.S.D.O.J.). This grant is administered through the Hamilton Fish National
Institute on School and Community Violence at George Washington University. This specific study was developed and implemented
by staff at: 1) East Carolina University’s Department of Criminal Justice; and 2) Florida State University’s Center for Educational
Research and Policy Studies. All points of view and opinions in this paper are those of the authors and do not necessarily
represent the official position or policies of East Carolina University, Florida State University, the Hamilton Fish National
Institute on School and Community Violence, the O.J.J.D.P., or the U.S.D.OJ. The authors would also like to thank Dr. Bill
Doerner and Jennifer Jolley for their support, editorial feedback, and insightful comments regarding earlier drafts of this
paper. 相似文献
242.
243.
This article surveys the voluminous economic literature on commoditybundling. While bundling has been widely studied, the vast majorityof the literature has focused on theoretical treatments of bundlingthat demonstrate a wide range of reasons why firms might engagein bundling. These papers generally contain restrictive assumptions,including assumptions regarding the existence of monopoly insome markets, and the nature of rivalry in others. The modelscontained in these papers also generally suppress the more obviousand ubiquitous reasons firms may use bundling. Moreover, thesemodels have not been subject to robustness checks, nor havetheir assumptions been tested empirically. This review of theeconomic literature generally confirms the US Solicitor General'sview in 3M v. LePage's regarding the underdeveloped state ofthe economics literature and its position that the US SupremeCourt should defer promulgation of antitrust standards for bundling.While the literature has demonstrated the possibility that bundlingcan generate anticompetitive harm, it does not provide a reliableway to gauge whether the potential for harm would outweigh anydemonstrable benefits from the practice. As a result, the widespreadapplication of the antitrust laws to bundling by firms can generatesignificant error costs by erroneously condemning or deterringefficient business practices. In the future, economists shouldseek to expand their understanding of both the anticompetitiveand procompetitive reasons firms engage in bundling. This willentail studying the reasons why bundling is adopted by firmswithout market power, relaxing the assumption of monopoly intheoretical models, and generating testable hypotheses and thedata to test them. 相似文献
244.
245.
246.
This reflection on major developments in the past, present, and future of the wider field of violence and trauma is a personal (and probably biased) sampling of what the authors hold to be important. The authors reviewed advances for victims and perpetrators of violence separately. For victims, the authors note that empirical research has established the potential traumatic impact of violence as well as various predictors of what makes persons vulnerable to adverse psychological consequences. The authors also note that the definitions of violence and trauma have evolved to include such behavioral patterns as stalking. Finally, encouraging evidence regarding the efficacy of exposure-based treatments for victims of violence is reviewed, as well as discouraging evidence regarding the efficacy of single-session debriefing following trauma. For the perpetrators, the importance of individual assessment in planning interventions is underscored, and advances in explicit and implicit assessment techniques are discussed. 相似文献
247.
248.
The effects of carbon monoxide and cyanide on the hepatic redox state and energy charge were investigated. Rats were used for the experiment under pentobarbital anesthesia. Immediately after laparotomy, a rat was placed in an animal chamber made of a transparent plastic box and exposed to a test gas for 3 min. Every test gas was produced in a gas chamber connected to the animal chamber with a flexible tube. HCN was produced from NaCN and H2SO4. In the CO inhalation experiment, various amounts of CO were introduced into the gas chamber. Immediately after an exposure, about 2 g liver was frozen in situ with a precooled clamp. Oozed blood from the wound surface was sampled. Concentrations of ATP, ADP, AMP, acetoacetate, and beta-hydroxybutyrate in hepatic mitochondria were determined, and the redox state and the energy charge were calculated. For cyanide as well as CO, significant negative correlations were found between the concentration in the blood and the redox state. The same held true for the energy charge. The redox state showed a slight increase at low concentrations of both gases; however, thereafter it began to decrease sharply with increases in concentrations. When concentrations of the toxicant in the blood reached certain levels, a kind of turning point, beyond which the redox state does not decrease any more, was observed. It was about 40% for HbCO and about 2.0 micrograms/ml for cyanide, and the points seemed to be related to the concentrations, beyond which cells are irreversibly damaged. On the other hand, the energy charge did not change at low concentrations. With an increase in toxicant concentrations, the energy charge decreased drastically. The rate of decrease in the energy charge became higher when blood concentrations exceeded certain levels. It was about 40% for HbCO and 2.0 micrograms/ml for cyanide. The presence of low levels of blood cyanide did not affect the relationship between the energy charge and the HbCO concentration. 相似文献
249.
250.
Contradictory findings from experiments designed for the reconstruction of the circumstances in crimes committed with firearms induced us to systematically investigate the conditions leading to the occurrence of non-typical bullet exit wounds. For this purpose, skin samples and pig heads were fired at with different types of small arms and, on the exit side, the skin was brought into contact with various materials. The bullet exits were investigated morphologically and by means of emission spectrum analysis. The results from these investigations are classified and discussed. 相似文献