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   1712714篇
  免费   115586篇
  国内免费   5126篇
耳鼻咽喉   20344篇
儿科学   55369篇
妇产科学   43263篇
基础医学   241741篇
口腔科学   41381篇
临床医学   161978篇
内科学   331442篇
皮肤病学   29992篇
神经病学   147986篇
特种医学   65973篇
外国民族医学   379篇
外科学   246439篇
综合类   33703篇
现状与发展   2篇
一般理论   624篇
预防医学   145700篇
眼科学   36494篇
药学   121597篇
  7篇
中国医学   4064篇
肿瘤学   104948篇
  2021年   15316篇
  2019年   15839篇
  2018年   42590篇
  2017年   32979篇
  2016年   37393篇
  2015年   20893篇
  2014年   28548篇
  2013年   42253篇
  2012年   65137篇
  2011年   82249篇
  2010年   53517篇
  2009年   44215篇
  2008年   75944篇
  2007年   82370篇
  2006年   59436篇
  2005年   59822篇
  2004年   58537篇
  2003年   57024篇
  2002年   53124篇
  2001年   62945篇
  2000年   64474篇
  1999年   54271篇
  1998年   17225篇
  1997年   15506篇
  1996年   14928篇
  1995年   14152篇
  1994年   13156篇
  1993年   12375篇
  1992年   42563篇
  1991年   41715篇
  1990年   40292篇
  1989年   38120篇
  1988年   35304篇
  1987年   34383篇
  1986年   32808篇
  1985年   31329篇
  1984年   23868篇
  1983年   20332篇
  1982年   12720篇
  1981年   11119篇
  1979年   21293篇
  1978年   15343篇
  1977年   12469篇
  1976年   12309篇
  1975年   12383篇
  1974年   15104篇
  1973年   14712篇
  1972年   13513篇
  1971年   12563篇
  1970年   11613篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
101.
102.
103.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
104.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
105.
106.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
107.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
108.
109.
In 1963, Goffman argued that forming a group based on shared stigma may provide benefits. However, there is no empirical research on whether perception that a separate, unique, coherent group exists (i.e., group entitativity) influences coping, such as educating others or secrecy, for the stigmatized individual or his or her spouse. Further, little is known about how spouses influence each other in terms of promoting the education of others about a stigmatizing condition, especially when it comes to the role of believing that stigma-based groups, to which they may both belong, exist. This study provides a step toward bridging this gap in the research by applying the label management model in efforts to understand coping for couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). This study included 50 married couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). We found that group entitativity related to those with AATD counterbalanced the influence of genetic stigma on spouses’ intentions to keep the diagnosis secret or to educate others about it. Intrapersonal and interpersonal influences appeared among spouses. Attention is needed on the power of creating groups for stigmatized persons and their relatives. Indeed, people live within a dynamic world of group entities, and multiple social identities including spousal and familial. While attention has been paid to the diffusion of stigmas to loved ones, less has been paid to the uplift of group entities for them.  相似文献   
110.
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