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   9927篇
  免费   843篇
  国内免费   30篇
耳鼻咽喉   64篇
儿科学   372篇
妇产科学   292篇
基础医学   1318篇
口腔科学   78篇
临床医学   1426篇
内科学   1750篇
皮肤病学   118篇
神经病学   1131篇
特种医学   196篇
外科学   928篇
综合类   90篇
一般理论   15篇
预防医学   1664篇
眼科学   89篇
药学   744篇
中国医学   4篇
肿瘤学   521篇
  2024年   18篇
  2023年   136篇
  2022年   147篇
  2021年   337篇
  2020年   255篇
  2019年   382篇
  2018年   392篇
  2017年   330篇
  2016年   370篇
  2015年   325篇
  2014年   435篇
  2013年   614篇
  2012年   856篇
  2011年   893篇
  2010年   447篇
  2009年   341篇
  2008年   624篇
  2007年   645篇
  2006年   556篇
  2005年   496篇
  2004年   475篇
  2003年   409篇
  2002年   387篇
  2001年   91篇
  2000年   58篇
  1999年   66篇
  1998年   65篇
  1997年   46篇
  1996年   53篇
  1995年   42篇
  1994年   34篇
  1993年   40篇
  1992年   48篇
  1991年   38篇
  1990年   41篇
  1989年   34篇
  1988年   33篇
  1987年   25篇
  1986年   26篇
  1985年   29篇
  1984年   25篇
  1983年   17篇
  1982年   10篇
  1981年   8篇
  1980年   7篇
  1977年   7篇
  1976年   12篇
  1975年   8篇
  1974年   7篇
  1972年   7篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
991.
Mutations in the nebulin gene can cause severe congenital nemaline myopathy   总被引:5,自引:0,他引:5  
Previously, we reported results indicating that nebulin was the gene causing the typical form of autosomal recessive nemaline (rod) myopathy. Here we describe the identification of mutations in the nebulin gene in seven offspring of five families affected by the severe congenital form of nemaline myopathy. One pregnancy was terminated on the grounds of foetal abnormality, while six affected infants died at ages ranging from the first day of life to 19 months. Only three of the six neonates were able to establish spontaneous respiration. Three had arthrogryposis. In three of the five families, the mutations were located in exon 184. These mutations are predicted to cause absence of the C-terminal part of nebulin.  相似文献   
992.
The effects of normal aging on sleep spindle and K-complex production.   总被引:3,自引:0,他引:3  
OBJECTIVES: Despite a relatively large body of literature describing the characteristics of sleep spindles and K-complexes in young adults, relatively little research has been conducted in older individuals. The general consensus from the few studies that have addressed this issue is that there is a progressive decrease in the number of spindles and K-complexes with age, although there is large intra-individual variation. Whether or not these changes are an inevitable consequence of the aging process can be addressed by studying healthy older adults who provide an example of the effects of age independently from those of disease.METHODS: Fourteen young adults (mean age=21.4+/-2.5 years) and 20 older adults (mean age=75.5+/-6.3 years) participated in the study. All subjects were neurologically and medically healthy and were not taking any medications with a known effect on the central nervous system or sleep. For each subject, a number of characteristics were determined including the number, density (SS/min), amplitude and frequency of all spindles as well as the number and density of K-complexes (KC/min).RESULTS: Spindle number, density and duration as well as K-complex number and density were all significantly lower in the elderly compared to the young adults. The EEG frequency within the spindles was significantly higher in the elderly, although the absolute difference was less than 0.5 Hz. Multiple regression analysis indicated that spindle duration and K-complex density were able to predict over 90% of the variance in age.CONCLUSIONS: The age-related decrease in sleep spindle and K-complex density is consistent with previous reports and may be interpreted as an age-related alteration of thalamocortical regulatory mechanisms.  相似文献   
993.
994.
995.
BackgroundPatient‐reported outcome measures (PROMs) are questionnaires that collect health outcomes directly from the people who experience them. This review critically synthesizes information on generic and selected condition‐specific PROMs to describe trends and contemporary issues regarding their development, validation and application.MethodsWe reviewed academic and grey literature on validated PROMs by searching databases, prominent websites, Google Scholar and Google Search. The identification of condition‐specific PROMs was limited to common conditions and those with a high burden of disease (eg cancers, cardiovascular disorders). Trends and contemporary issues in the development, validation and application of PROMs were critically evaluated.ResultsThe search yielded 315 generic and condition‐specific PROMs. The largest numbers of measures were identified for generic PROMs, musculoskeletal conditions and cancers. The earliest published PROMs were in mental health‐related conditions. The number of PROMs grew substantially between 1980s and 2000s but slowed more recently. The number of publications discussing PROMs continues to increase. Issues identified include the use of computer‐adaptive testing and increasing concerns about the appropriateness of using PROMs developed and validated for specific purposes (eg research) for other reasons (eg clinical decision making).ConclusionsThe term PROM is a relatively new designation for a range of measures that have existed since at least the 1960s. Although literature on PROMs continues to expand, challenges remain in selecting reliable and valid tools that are fit‐for‐purpose from the many existing instruments.Patient or public contributionConsumers were not directly involved in this review; however, its outcome will be used in programmes that engage and partner with consumers.  相似文献   
996.
997.
SUMMARY. Bile acids may play a role in the pathogenesis of Barrett’s esophagus (BE). Bile composition can be influenced by oral administration of ursodeoxycholic acid (UDCA). We prospectively investigated the effect of proton pump inhibitors (PPI) supplemented with UDCA in vivo in patients with BE. Patients with no or low‐grade dysplasia who were clinically asymptomatic on PPI were eligible for the study. In order to exclude the effects of acid reflux, all patients were initially treated with 40 mg esomeprazole (ESO) twice daily for 6 months and continued on this dose till the end of the study (t = 12 months). During a period of 6 months (t = 6 month – t = 12 month) patients were treated with oral UDCA (600 mg twice daily). Patients underwent endoscopy at t = 0 months, t = 6 months and t = 12 months with multiple biopsies of the distal and proximal BE segment, normal squamous and gastric cardia. In addition, pH was measured at t = 0 months and t = 6 months using a BRAVO wireless pH capsule. Bile was sampled at the beginning of the UDCA treatment and 6 months later (t = 6 month and t = 12 month). All biopsies were reviewed for the extent of metaplasia, dysplasia, and acute and chronic inflammation. In addition, proliferation (Ki67), differentiation (villin, cytokeratins 7 and 20) and inflammation (COX‐2) were investigated by immunohistochemistry (IHC). Nine patients (mean age 60 years, median BE length 7 cm) were included, of whom six had no dysplasia and three had low‐grade dysplasia. pH measurements revealed a normal acid exposure in most patients at t = 0 and t = 6 months. In addition, bile composition analysis demonstrated the efficacy of UDCA. Combining the results of both phases of the study, no significant changes were seen in any of the histological or IHC parameters. Differentiation and proliferation parameters showed no significant changes. In this study, in BE patients who were clinically asymptomatic on PPI, increasing the PPI dose to the maximum for 6 months followed by the addition of UDCA for 6 months did not result in significant histological or IHC changes in their BE.  相似文献   
998.
999.
This article describes a qualitative research project using a combination of reflection and action research. Eight experienced registered nurses identified their need to 'get it right under pressure' in their work in palliative care. Participants collaborated in generating and evaluating an action plan to enhance the likelihood of getting palliative nursing care right, under pressure, more often.  相似文献   
1000.
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