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   2603篇
  免费   204篇
  国内免费   17篇
耳鼻咽喉   12篇
儿科学   48篇
妇产科学   34篇
基础医学   135篇
口腔科学   24篇
临床医学   385篇
内科学   311篇
皮肤病学   18篇
神经病学   96篇
特种医学   24篇
外科学   139篇
综合类   198篇
现状与发展   1篇
预防医学   1040篇
眼科学   9篇
药学   269篇
  5篇
中国医学   23篇
肿瘤学   53篇
  2024年   22篇
  2023年   98篇
  2022年   157篇
  2021年   189篇
  2020年   178篇
  2019年   226篇
  2018年   177篇
  2017年   137篇
  2016年   111篇
  2015年   129篇
  2014年   170篇
  2013年   197篇
  2012年   142篇
  2011年   128篇
  2010年   113篇
  2009年   123篇
  2008年   100篇
  2007年   85篇
  2006年   52篇
  2005年   52篇
  2004年   34篇
  2003年   35篇
  2002年   27篇
  2001年   24篇
  2000年   27篇
  1999年   19篇
  1998年   14篇
  1997年   10篇
  1996年   3篇
  1995年   9篇
  1994年   6篇
  1993年   2篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   6篇
  1984年   4篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1977年   1篇
排序方式: 共有2824条查询结果,搜索用时 15 毫秒
91.
Very much an exercise in historical reconstruction, this article is concerned with the development of the first version of the Afghan NDCS. It is hoped that this domain of enquiry will contribute to discussions around the ‘governance of drug policy’ in this special issue of the International Journal of Drug Policy by focusing on how different policy actors operate in influencing the policy process; or parts thereof. More specifically, exploration of the formulation of the Strategy does much to help us understand not only the origins and shifting nature of ownership of drug policy within Afghanistan but also the relationship between the NDCS and the broader normative expectations of what has been referred to as the global drug prohibition regime (Andreas & Nadelmann, 2006, p. 38). As will be discussed, while indisputably the product of a process of policy transfer involving a number of non-Afghan actors – and as such arguably not always appropriate to the peculiarities of the drug market within the country – it can be argued that the 2003 National Drug Control Strategy fulfilled a useful functional role that in many ways exceeded its utility as a guiding document beyond the confines of Kabul.  相似文献   
92.
93.
BackgroundThis study aimed to determine between-country differences and changes over time in the portrayal of youth risk behaviors in films rated for youth in Argentina, Brazil, Mexico and the United States.MethodsContent and ratings were analyzed for 362 films that were popular across all four countries from 2002 to 2009. Country-specific ratings were classified as either youth or adult, and Generalized Estimating Equations were used to determine between-country differences in the presence of tobacco, alcohol, drugs, sexual content, and violence in youth-rated films. Within-country differences in this content over time were also assessed, comparing films released from 2002 to 2005 with those released from 2006 to 2009.ResultsIn the US, films rated for youth were less likely to contain all five risk behaviors than in youth-rated films in Argentina, Brazil, and, when the “15 and older” rating was considered a youth rating, in Mexico. All three Latin American countries “downrated” films that received an adult rating in the US. Nevertheless, tobacco and drug use in youth-rated films declined over time in all countries, whereas moderate to extreme alcohol use and violence involving children or youth increased in all countries.ConclusionsTobacco and drug use have declined in popular US films, but these behaviors are still prevalent in films rated for youth across the Americas. The apparent success of advocacy efforts to reduce tobacco and other drugs in films suggests that similar efforts be directed to reduce alcohol portrayals.  相似文献   
94.
背景 自新医改以来,我国制定了一系列分级诊疗政策,但十余年来,我国离全面实现分级诊疗的目标仍存在较大差距,因此,对国家出台的分级诊疗相关政策进行系统的量化分析显得尤为重要。目的 评估我国推动分级诊疗所发布的政策文件效力和实施效果。方法 2020年9月,在北大法宝、中国知网、万方数据知识服务平台、百度搜索引擎和政府部门相关网站等以“分级诊疗”“分级医疗”“双向转诊”“基层首诊”为检索词检索2009-2019年国家及各部委颁布的政策文件,经筛选后获得236项有助于分级诊疗制度推进的政策文件。效力分为政策措施、政策目标、政策反馈、政策力度4 个维度,效果用基层医疗卫生机构急诊就诊人次数指标表示,通过构建多元回归模型对三类不同政策工具分级诊疗实施效果进行回归分析。结果 2009-2019年的政策数量变化趋势与政策整体效力变化趋势基本一致,政策平均效力较平稳波动,政策措施得分在3.00分左右(除外2013年),政策目标得分均≤2.50分(除外2019年),政策反馈的平均得分在2.25分,政策力度平均得分<2.44分。供给、需求、环境型三类政策工具的政策数量变化趋势基本一致,供给型和环境型政策数量基本高于需求型政策。供给型政策中,医疗卫生机构建设类占比最多(36.67%),资金投入与资源分配类的平均效力值最高(20.00分);需求型政策中,医保类最多(61.70%)且平均效力值最高(15.07分);环境型政策中,目标规划类最多(49.25%)且平均效力值最高(20.25分);供给型、需求型、环境型这三类政策工具对政策实施效果影响的回归系数分别为1.271 9、2.013 8和1.937 8(P均<0.10),滞后期在1~3年。结论 我国分级诊疗政策效力的提高主要得益于政策颁布数量的累计效应;4个评价维度中,政策措施平均得分较高,政策目标的量化度低,政策反馈要求模糊,政策力度缺乏高层级部门的推动;供给型和环境型政策的数量基本都高于需求型政策,政策效力的得分主要取决于政策措施,特别是供给型和环境型政策;三类政策工具均对我国分级诊疗的开展起到正向作用,且需求型政策无论从滞后期还是政策效果指向来看都最具优势。如何充分发挥需求型政策引导国民理性就医选择的促进作用,应引起政府部门的高度重视。  相似文献   
95.
This paper describes an individual with autism and high-level calendar calculation ability who could perform a set of unpractised letter/number association tasks. The savant’s performance was compared with that of two control participants, one a departmental secretary and the other a professor of mathematics. The facility with which the savant could master the rules governing the relationships between the series of items suggests that he possessed a flexibility of mental processing transcending his ability of calendar calculation. Furthermore, he could recalibrate previous knowledge to solve new hitherto unpractised tasks. When presented with novel problems, the savant, unlike the mathematician, made no initial errors at all on any of the presented tasks, thereby indicating his fast and spontaneous recognition of new rules and of new relationships between items. It is concluded that a cognitive style of ‘weak central coherence’ as adopted by autistic savants may protect single representations from being retained in the form of stable enduring wholes, and that such a segmentation strategy may allow for the transformation, reorganization and reconstruction of the relationship between single items of information.  相似文献   
96.
Wales, in 2013, was the first country in the United Kingdom to pass legislation introducing presumed (or deemed) consent for organ donation, and remains the only one. It was introduced in an attempt to increase the number of life-saving transplants taking place in the UK, in a move that policy makers hoped would mirror Spain’s success. More recently, pressure has been mounting for England to follow suit, with a public consultation currently in progress. However, the Welsh system has been far from a success, raising the question of why campaigners are so adamant that it should be replicated. Before the Welsh Government introduced the Human Transplantation (Wales) Act there had been no strong evidence to suggest it would make a difference, with countries boasting both high organ donation rates and presumed consent legislation demonstrating no clear causal relationship between the two facts. In addition, a recent report evaluating the Act has highlighted its failure to improve donation rates, and has even presented some potentially concerning statistics that may suggest a negative impact. This paper first considers presumed consent in other countries – Spain and Brazil – before illustrating the underwhelming progression of Wales’ new system and the need to look to other options.  相似文献   
97.
Drug discovery is an iterative cycle of identifying promising hits followed by lead optimization via bioisosteric replacements. In the search for compounds affording good bioactivity, equal importance should also be placed on achieving those with favorable pharmacokinetic properties. Thus, the balance and realization of both key properties is an intricate problem that requires great caution. In this editorial, the authors explore the available computational tools in the context of the extant of big data that has borne out via advents of the Omics revolution. As such, the selection of appropriate computational tools for analyzing the vast number of chemical libraries, target proteins and interactomes is the first step toward maximizing the chance for success. However, in order to realize this, it is also necessary to have a solid foundation on the big concepts of drug discovery as well as knowing which tools are available in order to give drug discovery scientists the best opportunity.  相似文献   
98.
简要介绍美国儿科药品审批政策并进行深入分析,总结其成功经验,为建立适合我国的儿科药品审批政策提供参考.  相似文献   
99.
As health equity researchers, we need to produce research that is useful, policy-relevant, able to be understood and applied, and uses integrated knowledge translation (KT) approaches. The Manitoba Centre for Health Policy and its history of working with provincial government as well as regional health authorities is used as a case study of integrated KT. Whether or not health equity research “takes the day” around the decision-making table may be out of our realm, but as scientists, we need to ensure that it is around the table, and that it is understood and told in a narrative way. However, our conventional research metrics can sometimes get in the way of practicality and clear understanding. The use of relative rates, relative risks, or odds ratios can actually be detrimental to furthering political action. In the policy realm, showing the rates by socioeconomic group and trends in those rates, as well as incorporating information on absolute differences, may be better understood intuitively when discussing inequity. Health equity research matters, and it particularly matters to policy-makers and planners at the top levels of decision-making. We need to ensure that our messages are based on strong evidence, presented in ways that do not undermine the message itself, and incorporating integrated KT models to ensure rapid uptake and application in the real world.  相似文献   
100.
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