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   31050篇
  免费   1541篇
  国内免费   5篇
各国政治   1348篇
工人农民   1410篇
世界政治   2145篇
外交国际关系   1053篇
法律   20345篇
中国共产党   8篇
中国政治   279篇
政治理论   5753篇
综合类   255篇
  2021年   164篇
  2020年   579篇
  2019年   641篇
  2018年   818篇
  2017年   896篇
  2016年   974篇
  2015年   713篇
  2014年   774篇
  2013年   3161篇
  2012年   842篇
  2011年   895篇
  2010年   820篇
  2009年   868篇
  2008年   915篇
  2007年   938篇
  2006年   934篇
  2005年   829篇
  2004年   810篇
  2003年   782篇
  2002年   756篇
  2001年   1161篇
  2000年   1028篇
  1999年   842篇
  1998年   452篇
  1997年   323篇
  1996年   375篇
  1995年   347篇
  1994年   352篇
  1993年   350篇
  1992年   558篇
  1991年   596篇
  1990年   578篇
  1989年   512篇
  1988年   565篇
  1987年   496篇
  1986年   587篇
  1985年   549篇
  1984年   435篇
  1983年   413篇
  1982年   344篇
  1981年   322篇
  1980年   253篇
  1979年   361篇
  1978年   224篇
  1977年   184篇
  1976年   168篇
  1975年   213篇
  1974年   235篇
  1973年   176篇
  1972年   172篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
In recent years, legislators in all fifty states have given grandparents rights to petition for visitation privileges with grandchildren that can be enforced over parental objections. Grandparent visitation rights reflect an effort to protect meaningful relationships children enjoy with nonparental caregivers, enlist the assistance of extended family when the child's nuclear family is disrupted, and defend the interests of grandparents themselves. This psycholegal analysis explores the direct and indirect consequences of grandparent visitation statutes for family functioning. Statutory provisions are summarized, and the effects of these statutes are evaluated in light of what is known about the role of grandparents in child development, how courts evaluate children's "best interests" in grandparent visitation disputes, and how these statutes can alter family functioning in informal ways. The authors conclude that there are risks as well as benefits to children and families in grandparent visitation statutes, and suggest directions for procedural and statutory reform.  相似文献   
83.
Kornai's thesis that shortage results from demand expansions bred by the soft budget constraint, derives from his implicit assumption that price regimes of input and output firms are different. Since any firm is both an input and an output firm, which discards the assumption as logically untenable, excess demand can only turn up because of lower than contracted inputs of labor and management that are not offset by an adequate downward adjustment of earnings. Expansions of demand that appear to be autonomous, are incited by uncertain deliveries of inputs, that is, by inefficiency (of output firms) as well. A by far the largest part of excess demand can be explained by state preferences for fast growth. As planners are more successful in generating investment, and the ensuing consumer, demand than in expanding production, shortage is inevitable regardless of the character of the firms' budget constraints.  相似文献   
84.
A simple and sensitive method is described for quantitative analysis of chlorpromazine in blood, serum, urine and tissue homogenate. The chlorpromazine cation radical produced by adding perchloric acid and 2,3-dichloro-5,6-dicyano-p-benzoquinone to the sample can be detected by the ESR method at room temperature. The sensitivity limit is 10 ng, that is, 20 μl of the solution containing 0.5 μg chlorpromazine/ml. The time needed for the measurement is within 10 min. The chlorpromazine radical thus produced is very stable; for example, 95% of the radical was observed after 24 h. The advantage of this method is discussed by comparing with the ordinary spectrophotometry which requires the purification of the sample.  相似文献   
85.
86.
Although there has been speculation regarding the pervasiveness and nature of judicial decisions regarding life-sustaining medical treatment (LSMT), no attempt has been made to empirically assess their prevalence or the issues they address. An exploratory study utilizing a mail survey of a nationwide random sample (N = 905) of state trial court judges was conducted to provide initial information regarding this decision-making process. Twenty-two percent of the responding judges had heard at least one LSMT case, and judicial review did not appear endemic to particular states. The number of judges hearing LSMT cases dropped from 1975 to 1981 but has increased since then. Three major issues predominate: patient competency, appointment of a surrogate decisionmaker, and resolution of the ultimate issue of forgoing LSMT. Relatively few cases either contested a prior directive's validity or involved imposing sanctions for instituting or forgoing LSMT. Although subject to different interpretations, the results suggest the courts are having a significant impact on certain aspects of the LSMT decision-making process. However, the infrequency with which any one judge is called upon to make an LSMT decision causes concern about the judiciary's ability to respond in a timely and appropriate manner. With their potential for a profound effect on the actions of health care providers, greater attention to this decision-making process is warranted.  相似文献   
87.
88.
89.
The possible contribution of poppy seed foods to positive opiate urinalysis results, especially from foods available in the Pacific Rim area, has recently become an issue for the U.S. Army Forensic Toxicology Drug Testing Laboratory in Hawaii. To assess the likelihood of this possible contribution, seven different poppy seed food products were consumed by male and female volunteers, and urine specimens were collected at time increments up to either 24 or 72 h. Specimens were evaluated for opiates using Roche Abuscreen radioimmunoassay (RIA), and all RIA positive specimens were analyzed for morphine and codeine using gas chromatography/mass spectrometry (GC-MS). Poppy seed cake, bagels, muffins, and rolls did not contain sufficient quantities of poppy seeds to give rise to opiate positive specimens by U.S. Department of Defense (DOD) GC-MS cutoff levels (morphine = 4000 ng/mL, codeine = 2000 ng/mL), although a number of specimens were positive by National Institute on Drug Abuse (NIDA) cutoff levels (morphine and codeine = 300 ng/mL). However, ingestion of poppy seed streusel or Danish pastry led to confirmed morphine and codeine positive specimens, irrespective of the use of DOD or NIDA confirmation cutoff values. In addition, significant amounts of codeine were observed in a number of these specimens. These findings argue against the unqualified application of previously published quantitative guidelines for eliminating poppy seed ingestion as a possible cause for a positive opiate urinalysis result.  相似文献   
90.
本文是2006年5月25日在香港大学召开的"中非人力资源开发与合作"学术研讨会的系列论文之一。作者基于贫困的持续性与其各构成要素的相互关联性这一机理,运用比较研究方法,测度和评析尼日利亚与中国的减贫政策及其实施效应,反映了国际学术界对减贫问题的研究动态。诚然,本文仅代表作者的观点。  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