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   16668篇
  免费   469篇
各国政治   606篇
工人农民   717篇
世界政治   1180篇
外交国际关系   598篇
法律   10266篇
中国共产党   34篇
中国政治   189篇
政治理论   3380篇
综合类   167篇
  2021年   112篇
  2020年   231篇
  2019年   256篇
  2018年   354篇
  2017年   386篇
  2016年   423篇
  2015年   306篇
  2014年   373篇
  2013年   1625篇
  2012年   391篇
  2011年   447篇
  2010年   351篇
  2009年   425篇
  2008年   514篇
  2007年   511篇
  2006年   494篇
  2005年   459篇
  2004年   480篇
  2003年   381篇
  2002年   368篇
  2001年   657篇
  2000年   589篇
  1999年   445篇
  1998年   245篇
  1997年   202篇
  1996年   208篇
  1995年   178篇
  1994年   189篇
  1993年   175篇
  1992年   316篇
  1991年   386篇
  1990年   344篇
  1989年   321篇
  1988年   341篇
  1987年   321篇
  1986年   321篇
  1985年   298篇
  1984年   283篇
  1983年   252篇
  1982年   170篇
  1981年   206篇
  1980年   150篇
  1979年   183篇
  1978年   143篇
  1977年   109篇
  1976年   103篇
  1975年   108篇
  1974年   125篇
  1973年   136篇
  1972年   92篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
"Brain death," the determination of human death by showing the irreversible loss of all clinical functions of the brain, has become a worldwide practice. A biophilosophical account of brain death requires four sequential tasks: (1) agreeing on the paradigm of death, a set of preconditions that frame the discussion; (2) determining the definition of death by making explicit the consensual concept of death; (3) determining the criterion of death that proves the definition has been fulfilled by being both necessary and sufficient for death; and (4) determining the tests of death for physicians to employ at the patient's bedside to demonstrate that the criterion of death has been fulfilled. The best definition of death is "the cessation of functioning of the organism as a whole." The whole-brain criterion is the only criterion that is both necessary and sufficient for death. Brain death tests are used only in the unusual case in which a patient's ventilation is being supported. Brain death critics have identified weaknesses in its formulation. But despite its shortcomings, the whole-brain death formulation comprises a concept and public policy that make intuitive and practical sense and that has been well accepted by many societies.  相似文献   
112.
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   
113.
Ethanol was determined by gas chromatography in a variety of tissues and body fluids secured at autopsy in 61 cases. The specimens tested included right and left heart blood, femoral blood, pericardial fluid, cerebrospinal fluid, vitreous humor, urine, stomach contents, and brain. Statistical analysis of the cases revealed no significant differences among the various blood sites tested. However, the variations in blood ethanol concentrations among the various sampling sites within each case were as follows: 40 cases showed differences of less than 25%; 16 cases revealed variability between 25% and 50%, 4 cases had differences exceeding 50%. In one case, satisfactory blood analyses could not be accomplished. The larger variances occurred especially in those instances in which stomach alcohol concentration was 0.50% or greater. In one case, the variability amongst the different blood sites exceeded 400% (femoral blood--0.043%, right atrium--0.070%, root of aorta--0.156%); the brain was 0.050%, and the stomach contents was 1.2%. For all 61 cases, variances in blood alcohol content among the different sampling sites in a single cadaver ranged from 1.8 to 428%.  相似文献   
114.
Conclusion The Regulations appear to have reinforced the protection available to software producers under United Kingdom law. The provisions of the Software Directive and the Regulations are complex and not without significant inconsistencies which are likely to prove to be a source of litigation. The drafters of the Regulations chose, unlike many of its European partners, not to adopt the wording of the Software Directive but to write their own interpretation, adding an element of uncertainty to the law in this area, which is perhaps inevitable bearing in mind the linguistic problems of translating and interpreting any directive coupled with the ambiguity and omission of definitions of several key terms. More important, however, than any academic argument will be the practical impact of the new law and its effectiveness in achieving its aim.  相似文献   
115.
For helpful suggestions and criticism I am grateful to Delf Buchwald (Göttingen), Malte Dießelhorst (Göttingen), Ralf Dreier (Göttingen), Bonnie Litschewski Paulson (Göttingen and St. Louis), Martin Schulte (Münster), Alexander Somek (Vienna), and Kenneth I. Winston (Boston). In correspondence, Walter Ott (Zurich) and Carola Vulpius (Dresden) responded in a most helpful way to my queries.  相似文献   
116.
117.
This paper examines nine cases of “spinback,” the flow back to laboratories of technical advantage from technology transfer activities. The benefits revealed in the cases are discussed and assessed for their value to the participating laboratories and the scientists involved. The objective of this study was to explore and test the feasibility of undertaking a comprehensive study of the value of spinback in order to encourage support for technology transfer activities by middle management in a laboratory. Spinback is defined as the phenomenon by which scientists’ and engineers’ participation in technology utilization activities results in a technically valuable flow back to their laboratories or organizations, thereby increasing or improving techical capability. It was anticipated that this exploration would provide evidence that the phenomenon does occur, with important consequences for the organization.  相似文献   
118.
Deoxyribonucleic acid (DNA) typing of ribosomal ribonucleic acid (rRNA) genes was performed with a polymerase chain reaction (PCR) assay for species identification. A variable region of the 28S ribosomal RNA gene was amplified with primers complementary to flanking sequences phylogenetically well conserved. The products of twelve animal DNAs (human, Japanese monkey, dog, cattle, pig, cat, rabbit, mouse, rat, chicken, frog, and fish) were separated by polyacrylamide gel electrophoresis, each revealing a few bands ranging from 150 to 100 base pairs. The band patterns obtained from each DNA sample differed in number and size, which indicates the applicability of the method to species identification. Samples containing either as little as 1 pg of DNA or degraded DNA of 0.2 to 0.5 kb in length were able to give detectable bands. Postmortem human tissue DNAs were tested as an example. They showed a pattern identical to the human control one, which was distinct from those of the other animals examined.  相似文献   
119.
In the forensic science laboratory, the recovery of spermatozoa from vaginal swabs, or vaginal cells from penile swabs, can help determine if sexual intercourse may have taken place. There are several methods used to recover spermatozoa and cells from the swabs before visualisation on a microscope slide and most of these methods use water. Phosphate buffered saline (PBS) is a non-toxic solution used in many biological laboratories. Unlike water, PBS prevents cells rupturing or shrivelling up due to osmosis. This study demonstrates that PBS can be used for the extraction of spermatozoa and cells from swabs and that PBS does not affect subsequent DNA profiling.  相似文献   
120.
Citizen suit provisions, which give proregulatory interests access to the federal courts, can be used by Congress to increase the courts' role in regulatory policy. I analyze 284 environmental regulation bills reported favorably out of committee and show that committee support for citizen suits is a function of the committee's policy goals and the political context in which the bills are generated. These findings indicate that Congress deliberately uses judicial procedures as instruments of political control and that scholars examining judicial policymaking must include legislative goals in the list of explanatory factors.  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