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   2639篇
  免费   99篇
  国内免费   27篇
管理学   139篇
民族学   28篇
人口学   49篇
丛书文集   170篇
理论方法论   178篇
综合类   1631篇
社会学   396篇
统计学   174篇
  2024年   1篇
  2023年   21篇
  2022年   18篇
  2021年   28篇
  2020年   52篇
  2019年   51篇
  2018年   71篇
  2017年   69篇
  2016年   73篇
  2015年   75篇
  2014年   159篇
  2013年   341篇
  2012年   161篇
  2011年   149篇
  2010年   106篇
  2009年   138篇
  2008年   138篇
  2007年   143篇
  2006年   167篇
  2005年   153篇
  2004年   116篇
  2003年   95篇
  2002年   108篇
  2001年   115篇
  2000年   59篇
  1999年   33篇
  1998年   22篇
  1997年   21篇
  1996年   18篇
  1995年   10篇
  1994年   14篇
  1993年   9篇
  1992年   8篇
  1991年   6篇
  1990年   5篇
  1989年   4篇
  1988年   4篇
  1987年   2篇
  1981年   1篇
  1977年   1篇
排序方式: 共有2765条查询结果,搜索用时 296 毫秒
61.
Differences in patient characteristics, including age, sex, and race influence the safety and effectiveness of drugs, biologic products, and medical devices. Here we provide a summary of the topics discussed during the opening panel at the 2018 Johns Hopkins Center for Excellence in Regulatory Science and Innovation symposium on Assessing and Communicating Heterogeneity of Treatment Effects for Patient Subpopulations: Challenges and Opportunities. The goal of this session was to provide a brief overview of FDA-regulated therapeutics, including drugs, biologics and medical devices, and some of the major sources of heterogeneity of treatment effects (HTE) related to patient demographics, such as age, sex and race. The panel discussed the US Food and Drug Administration's role in reviewing and regulating drugs, devices, and biologic products and the challenges associated with ensuring that diverse patient populations benefit from these therapeutics. Ultimately, ensuring diverse demographic inclusion in clinical trials, and designing basic and clinical research studies to account for the intended patient population's age, sex, race, and genetic factors among other characteristics, will lead to better, safer therapies for diverse patient populations.  相似文献   
62.
科技术语在不同语言之间的翻译是一个复杂的语义匹配过程,如何在考虑相关术语使用现状的基础上将新产生的科技术语准确翻译为其它语言是科技工作者和术语研究者关注的重要问题。以语义场理论为分析框架,通过分析以"水资源管理"及其相关术语为代表的英汉互译,结果发现:不同科技术语在同一语义场所涵盖的语义范围将会随着相关研究深化带来的术语界定细化而发生相应的动态变化;新兴科技术语的翻译要充分考虑其所在语义场其它相关科技术语的翻译先例和使用现状所带来的影响,在翻译准确性和解读便利性之间做出适当的平衡。这是造成"水资源管理"及相关术语英汉互译处理极为复杂的重要原因之一,需要科技翻译者在工作实践中多加注意。  相似文献   
63.
Although many children across cultures are victims of physical abuse, few treatment models target these children and their parents. In Sweden, Combined Parent–Child Cognitive Behavioural Therapy for families at risk for child physical abuse has been successfully used according to pretreatment and posttreatment studies. However, few studies have explored how physically abused children experience treatment. This study includes 20 physically abused children aged 9–17 who completed Combined Parent–Child Cognitive Behavioural Therapy. Children had a positive overall impression of the treatment and highlighted addressing the abuse, as well as processing their experiences as particularly essential. Children described a positive transformation in their family life as a result of treatment, including violence cessation and bonding among family members. Children experienced the intervention as inclusive and child‐friendly. The implications of the promising findings are discussed.  相似文献   
64.
In late-phase confirmatory clinical trials in the oncology field, time-to-event (TTE) endpoints are commonly used as primary endpoints for establishing the efficacy of investigational therapies. Among these TTE endpoints, overall survival (OS) is always considered as the gold standard. However, OS data can take years to mature, and its use for measurement of efficacy can be confounded by the use of post-treatment rescue therapies or supportive care. Therefore, to accelerate the development process and better characterize the treatment effect of new investigational therapies, other TTE endpoints such as progression-free survival and event-free survival (EFS) are applied as primary efficacy endpoints in some confirmatory trials, either as a surrogate for OS or as a direct measure of clinical benefits. For evaluating novel treatments for acute myeloid leukemia, EFS has been gradually recognized as a direct measure of clinical benefits. However, the application of an EFS endpoint is still controversial mainly due to the debate surrounding definition of treatment failure (TF) events. In this article, we investigate the EFS endpoint with the most conservative definition for the timing of TF, which is Day 1 since randomization. Specifically, the corresponding non-proportional hazard pattern of the EFS endpoint is investigated with both analytical and numerical approaches.  相似文献   
65.
The problem of comparing, contrasting and combining information from different sets of data is an enduring one in many practical applications of statistics. A specific problem of combining information from different sources arose in integrating information from three different sets of data generated by three different sampling campaigns at the input stage as well as at the output stage of a grey-water treatment process. For each stage, a common process trend function needs to be estimated to describe the input and output material process behaviours. Once the common input and output process models are established, it is required to estimate the efficiency of the grey-water treatment method. A synthesized tool for modelling different sets of process data is created by assembling and organizing a number of existing techniques: (i) a mixed model of fixed and random effects, extended to allow for a nonlinear fixed effect, (ii) variogram modelling, a geostatistical technique, (iii) a weighted least squares regression embedded in an iterative maximum-likelihood technique to handle linear/nonlinear fixed and random effects and (iv) a formulation of a transfer-function model for the input and output processes together with a corresponding nonlinear maximum-likelihood method for estimation of a transfer function. The synthesized tool is demonstrated, in a new case study, to contrast and combine information from connected process models and to determine the change in one quality characteristic, namely pH, of the input and output materials of a grey-water filtering process.  相似文献   
66.
The symmetric treatment of an asymmetric approach to factor analysis is shown to provide accurate communality estimates. In comparison with existing estimates including upper and lower bounds, the present approach is shown to be superior. In one example with known communalities, the present approach perfectly captures those communalities. In two empirical examples, it is shown to produce better communality estimates than any existing method.  相似文献   
67.
以长期水驱实验为基础,建立了等效水驱砂岩储层孔喉结构变化的三维网络模拟模型,结合三维微粒运移机制和有限差分求解方法,得到了长期水驱砂岩油藏孔喉结构变化规律:(1) 冲刷后喉道半径呈增加趋势,喉道半径变化范围变大,极小喉道半径呈微弱减小趋势;(2) 孔隙网络模型中冲刷半径扩大的孔道分布形式与原始孔隙网络结构密切相关,并非所有的大孔道都串联起来贯穿岩芯孔隙网络的两个端面,但入口端和出口端部分大孔道相互连通,形成端面上的大孔道网络群。网络模拟注水结果结合采油井测试,可为注水剖面的调整提供更加可靠的依据。  相似文献   
68.
Barbara Brenner, JD, was the Executive Director of Breast Cancer Action (BCA) from 1995–2010. Before that, she was a longtime activist in the anti-war movement and an attorney who, for most of her career, practiced public policy law. After she was diagnosed with breast cancer in 1993 at the age of 41, she took the helm of BCA. Under her leadership, the organization moved into a position of national advocacy—demanding research on the causes and prevention of breast cancer, including the role of industrial pollutants. Barbara started the “Think Before You Pink” campaign, encouraging people to question whether companies that display pink ribbons actually produce products that harm women's health or generate any funds to fight breast cancer. Her blog, “Healthy Barbs,” challenged readers to critique routine healthcare practices and policies. Barbara received numerous awards, including a Jefferson Award for Public Service in 2007, the Smith College Medal in 2012, and the ACLU-Northern California's Lola Hanzel Courageous Advocacy Award in 2012. Barbara had a recurrence of breast cancer in 1996. She died of complications associated with amyotrophic lateral sclerosis, ALS, on May 10, 2013.  相似文献   
69.
奥巴马政府上台后,其主要致力于应对金融危机和反恐战争.对朝政策上,其在"巧实力"外交理念的指导下,寻求在外交、经济、军事、政治、法律和文化等所有政策工具中选择正确的工具或组合.针对朝核问题的敏感性和脆弱性,奥巴马政府倾向于"冷处理",继而"多管齐下",在合作外交的框架内展开更加灵活的外交活动,促使朝鲜重返六方会谈,继续以对话方式处理相关问题,不过美国也适度增强了对朝鲜的威慑力量,奥巴马政府仍对美朝关系正常化持一种谨慎态度.  相似文献   
70.
絮凝床是中山大学开发的一种新型水处理设备.这种水处理技术在我省已用于包括含动、植物油类的污水处理工程中,1996年我院首次把这种设备用于茂名热电厂合油(矿物油)污水处理,工程建成投产以来取得了令人满意的效果。  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