全文获取类型
收费全文 | 3802篇 |
免费 | 124篇 |
专业分类
各国政治 | 236篇 |
工人农民 | 127篇 |
世界政治 | 322篇 |
外交国际关系 | 159篇 |
法律 | 2550篇 |
中国政治 | 21篇 |
政治理论 | 489篇 |
综合类 | 22篇 |
出版年
2021年 | 39篇 |
2020年 | 75篇 |
2019年 | 79篇 |
2018年 | 100篇 |
2017年 | 107篇 |
2016年 | 101篇 |
2015年 | 65篇 |
2014年 | 107篇 |
2013年 | 390篇 |
2012年 | 115篇 |
2011年 | 110篇 |
2010年 | 65篇 |
2009年 | 58篇 |
2008年 | 91篇 |
2007年 | 104篇 |
2006年 | 108篇 |
2005年 | 104篇 |
2004年 | 108篇 |
2003年 | 108篇 |
2002年 | 94篇 |
2001年 | 176篇 |
2000年 | 154篇 |
1999年 | 85篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 26篇 |
1994年 | 32篇 |
1993年 | 31篇 |
1992年 | 71篇 |
1991年 | 78篇 |
1990年 | 67篇 |
1989年 | 90篇 |
1988年 | 89篇 |
1987年 | 78篇 |
1986年 | 77篇 |
1985年 | 68篇 |
1984年 | 37篇 |
1983年 | 42篇 |
1982年 | 24篇 |
1981年 | 30篇 |
1979年 | 34篇 |
1978年 | 27篇 |
1977年 | 29篇 |
1975年 | 32篇 |
1974年 | 30篇 |
1973年 | 37篇 |
1972年 | 35篇 |
1971年 | 30篇 |
1969年 | 24篇 |
排序方式: 共有3926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.
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
16.
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
17.
18.
19.
We consider the problem of drawing inferences within a legal framework when a person is a suspect for two separate offences. Although we are primarily concerned with scientific evidence the issue inevitably arises as to how that evidence interacts with other, non-scientific evidence. We show that, in this particular context, the evidence can be conveniently classified into three categories that concern, respectively: the first crime only; the second crime only; and evidence that relates to similarities between the two crimes. Two case examples are considered and we consider DNA, fibres and eyewitness evidence. These are viewed from the perspective of a prosecutor who has to decide whether or not to charge a suspect with one or both crimes. Graphical sensivity analyses are presented which have features that are not intuitively obvious. 相似文献
20.
This paper studies the impact of daily official foreign exchange interventions on the exchange rates in Croatia for the period from 1996 to 2004. Using the event study methodology and a variety of GARCH models reveals that the Croatian central bank was in a position to influence, to some extent, the level of the exchange rate during the period studied. This lends support to the view that foreign exchange intervention may be effective in emerging market economies. 相似文献