全文获取类型
收费全文 | 3951篇 |
免费 | 115篇 |
专业分类
各国政治 | 212篇 |
工人农民 | 127篇 |
世界政治 | 241篇 |
外交国际关系 | 135篇 |
法律 | 2680篇 |
中国政治 | 40篇 |
政治理论 | 608篇 |
综合类 | 23篇 |
出版年
2024年 | 39篇 |
2023年 | 155篇 |
2021年 | 56篇 |
2020年 | 49篇 |
2019年 | 48篇 |
2018年 | 65篇 |
2017年 | 83篇 |
2016年 | 86篇 |
2015年 | 62篇 |
2014年 | 76篇 |
2013年 | 377篇 |
2012年 | 103篇 |
2011年 | 115篇 |
2010年 | 80篇 |
2009年 | 80篇 |
2008年 | 102篇 |
2007年 | 117篇 |
2006年 | 124篇 |
2005年 | 108篇 |
2004年 | 101篇 |
2003年 | 109篇 |
2002年 | 96篇 |
2001年 | 174篇 |
2000年 | 146篇 |
1999年 | 91篇 |
1998年 | 39篇 |
1997年 | 33篇 |
1996年 | 29篇 |
1994年 | 31篇 |
1993年 | 27篇 |
1992年 | 74篇 |
1991年 | 85篇 |
1990年 | 76篇 |
1989年 | 96篇 |
1988年 | 90篇 |
1987年 | 76篇 |
1986年 | 86篇 |
1985年 | 81篇 |
1984年 | 43篇 |
1983年 | 51篇 |
1982年 | 30篇 |
1981年 | 36篇 |
1979年 | 32篇 |
1977年 | 29篇 |
1975年 | 32篇 |
1974年 | 33篇 |
1973年 | 34篇 |
1972年 | 33篇 |
1971年 | 25篇 |
1969年 | 25篇 |
排序方式: 共有4066条查询结果,搜索用时 15 毫秒
11.
C Moore S Browne I Tebbett A Negrusz W Meyer L Jain 《Forensic science international》1992,56(2):177-181
A new solid-phase extraction procedure for the determination of cocaine and benzoylecgonine in amniotic fluid, using high flow co-polymeric sorbents is reported. The recoveries of cocaine and benzoylecgonine within the range 0.1-1 mg/l were 95.7% and 50.3%, respectively. The use of high-flow sorbents allowed the easy extraction of amniotic fluid regardless of sample viscosity or physical nature. The use of these solid-phase columns provided many advantages over the more commonly used solvent extraction, including an increase in extraction speed and efficiency, reduced operator time, reduced solvent use and disposal volumes and exceptional extract quality. Further, the determination of amniotic fluid obtained from pregnant cocaine users may provide important information about handling of cocaine by the fetus at various gestational ages. The procedure was successfully applied to amniotic fluid from suspected cocaine abusers. 相似文献
12.
An improved method has been developed for the reliable classification of different C1R genetic variant forms from human serum or plasma. The method combines the use of neuraminidase-digested samples followed by monodimensional isoelectric focusing in the pH range 5 to 8 followed by immunoblotting. The method yields a simple pattern, with one major band in homozygote and two major bands in heterozygote cases. 相似文献
13.
14.
15.
This study examines a crucial question: What kind of effect do interdiction and other drug enforcement activities have on drug smuggling? Do they actually deter smuggling, or is their effect more one of disruption and displacement?... 相似文献
16.
Federal transportation officials assert that labor protections in the Urban Mass Transportation Act inhibit the propensity of local transit agencies to contract with private firms for services. The authors present results from a survey of a large sample of transit managers and econometric analysis to support their conclusion that labor protections do not appear to reduce the incidence of contracting. The labor protections, however, may be costly to transit management in other ways. The authors recommend actions, aside from repeal of labor protections, to increase contracting by local transit agencies. 相似文献
17.
Evaluating the Impact of Criminal Laws on HIV Risk Behavior 总被引:1,自引:0,他引:1
18.
Some features of early child care are more prominent in Norway than in other countries, such as emphasis on the outdoor environment. Of general relevance and interest is the form of day care provided by forest day-care centers. Three ideas form the development of these centers placed in wild areas. First, throughout history, Norwegians have had a close attachment to nature and some parents want to provide their children with outdoor experiences at an early age. Second, urging children to play outdoors characterizes the image many parents have of a happy, healthy childhood. Third, provision of day care for children has always been restricted in western countries, forcing parents to invent types of service that can become part of an ecological system that promotes healthy development.The forest day-care centers developed recently represent a supplement to the wide typology of child care in the 21st century. The article outlines the connections between these ideas in general European and western history and Norwegian history and presents debate and decisions about a question dating from the last half of the 1980s. It concludes that the forest day-care centers are perhaps only a modern form of the original kindergarten concept, which started in Europe and America as gardens for children not gardens of children. 相似文献
19.
20.
K. Michael Reynolds Pamala L. Griset Ernest Scott 《American Journal of Criminal Justice》2006,31(1):1-17
Many attempts have been made over the last several decades to improve communication among law enforcement agencies. This article
is a case study of a “low-level” data sharing project in Florida that could serve as a national model. The Florida Law Enforcement
Data Sharing Consortium is a partnership between the University of Central Florida and more than one hundred law enforcement
agencies. It offers an inexpensive, yet technically advanced alternative to the proprietary data sharing model. Its distributed
architecture was endorsed by the Markle Foundation, the 9/11 Commission, and the 2004 National Security Act. Civil liberties
concerns raised by this and other types of data sharing projects are discussed. 相似文献