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   7457篇
  免费   171篇
各国政治   466篇
工人农民   253篇
世界政治   536篇
外交国际关系   296篇
法律   4644篇
中国共产党   7篇
中国政治   59篇
政治理论   1342篇
综合类   25篇
  2022年   34篇
  2021年   56篇
  2020年   105篇
  2019年   137篇
  2018年   231篇
  2017年   202篇
  2016年   221篇
  2015年   157篇
  2014年   170篇
  2013年   741篇
  2012年   206篇
  2011年   209篇
  2010年   182篇
  2009年   215篇
  2008年   267篇
  2007年   283篇
  2006年   274篇
  2005年   194篇
  2004年   214篇
  2003年   171篇
  2002年   167篇
  2001年   348篇
  2000年   317篇
  1999年   212篇
  1998年   91篇
  1997年   88篇
  1996年   60篇
  1995年   58篇
  1994年   57篇
  1993年   39篇
  1992年   128篇
  1991年   146篇
  1990年   137篇
  1989年   132篇
  1988年   121篇
  1987年   129篇
  1986年   106篇
  1985年   101篇
  1984年   98篇
  1983年   87篇
  1982年   60篇
  1981年   80篇
  1980年   35篇
  1979年   75篇
  1978年   47篇
  1975年   38篇
  1974年   51篇
  1973年   57篇
  1972年   40篇
  1971年   34篇
排序方式: 共有7628条查询结果,搜索用时 15 毫秒
921.
922.
Diquat can be extracted with 1-butanol from high pH solution in the presence of several moderate reductants. The red colored reduced compound of diquat in water turns to a purple compound in 1-butanol. The absorption of the purple compound is 0.105 at 383 nm and 0.119 at 520 nm in 1 microgram diquat/ml 1-butanol. The latter value is a little higher than that of the red compound at 495 nm in water. The purple compound is much more stable than the red compound in water. More than 80% of 10 ppm diquat added can be extracted from serum, blood, tissues, urine and some drinks. The extraction with 1-butanol is useful for concentration of diquat contained in large volume. The lower limit of detection is 0.1 microgram/ml 1-butanol. Paraquat is insoluble in 1-butanol under the same condition. Therefore, this method is applicable for the determination of diquat when paraquat is also contained in the solution.  相似文献   
923.
A spectrophotometrical method for discrimination between sulfhemoglobin (SHb) and choleglobin was applied to analyses of the green pigments in epidermal blisters of decomposed cadavers. SHb appeared to be a predominant constituent of the pigments, although significant amounts of choleglobin, one third to one sixth of SHb, were also demonstrated. The present results indicate that the greenish discoloration of decomposed cadavers is due to formation of a mixture of SHb, choleglobin and possibly other denatured hemoglobin derivatives.  相似文献   
924.
925.
Reading the comparative analysis of federations as different, constitutionally and culturally, as Canada, the USA, Australia, India and Nigeria, to mention only a few, is to agree with the title of this review. The words are taken from the Introduction to Bakvis and Chandler and this review argues that use of the word "surprisingly" is misplaced. Much of the writing critical of federalism has been labouring under a misunderstanding of its dynamic nature and its underlying strengths.  相似文献   
926.
Police functions and services are currently based on three implicit basic conceptual units: the person, the process, and the product. Each one of these was the fundamental assumption for one of the three historical models of police science: the Personal Qualities Model, the Community Relations Model, and the Scientific Management Model. Although none of these models has ever been implemented in a pure form, modern police science is implicitly based on their three basic conceptual units which are applied to different but specific areas of police functions and services. However, these conceptual units have never been explicitly reconciled with each other, thus at times resulting in contradictory proposals. A comprehensive theory of police functions and services requires a conceptual framework for explicitly relating the person, the process, and the product. A two-dimensional framework is proposed based on a psychological and a sociological level of analysis.  相似文献   
927.
The feasibility of detecting methamphetamine and its major metabolite, amphetamine, in postmortem tissues over a 2-year period was examined. It is important to determine if the abuse and toxic effects of drugs can be proved from evidence found in decayed, submerged, or stained tissue materials. The blood, urine, liver, skeletal muscle, skin and extremity bones from rabbits given methamphetamine intravenously were kept at room temperature, under 4 different conditions: sealed in a test tube, dried in the open air, submerged in tap water and stained on gauze. Methamphetamine was present in all the samples, with slight change in concentration in case of sealed and air dried tissues. Changes varied in bones kept in water. There were considerable decreases in methamphetamine in blood and urine stains. Despite long term storage, drug abuse and/or toxicity could be determined, in all tissues examined.  相似文献   
928.
929.
Abstract: The Australian diplomatic service receives a fair degree of criticism, some misconceived, but some directed constructively at improving its economy and efficiency. The traditional objectives of Australian overseas representation are not questioned; rather the debate centres on the vast range of choice in the ways in which these broad objectives can be met—on such matters as how elaborately the task of overseas representation should be performed, where, and how large, overseas missions should be, how the diplomatic service should be staffed, and whether the pattern of coordination between the diplomatic service and other parts of the public service is appropriate. The complex issues involved in these areas of debate form part of the background against which the everyday work of the diplomatic service is set. This work includes political and economic reporting, the usual consular business, and “one-off” occasions ranging from the preparation of major bilateral treaties to war or revolution. Language and cultural differences make the carrying out of these tasks more difficult. Recruits to the diplomatic service are usually graduates in their mid-twenties with strong university qualifications, which are supplemented by formal training and by experience in different posts abroad and in Australia. The trend to greater specialization of diplomatic staff suggests a need for closer contact between the foreign service and other parts of the Australian Public Service, universities and the private sector. The past few years have been a period of questioning and criticism in all parts of the public sector, including the diplomatic service. At the same time the role played by the diplomatic service has grown more difficult. It is time that discussion focused on the key question—the need for comprehensive representation of Australia overseas—rather than on those who service this representation.  相似文献   
930.
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