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   5323篇
  免费   380篇
  国内免费   22篇
耳鼻咽喉   30篇
儿科学   71篇
妇产科学   51篇
基础医学   783篇
口腔科学   40篇
临床医学   593篇
内科学   1176篇
皮肤病学   84篇
神经病学   783篇
特种医学   314篇
外科学   824篇
综合类   14篇
预防医学   222篇
眼科学   40篇
药学   295篇
中国医学   6篇
肿瘤学   399篇
  2023年   62篇
  2022年   127篇
  2021年   290篇
  2020年   151篇
  2019年   241篇
  2018年   258篇
  2017年   175篇
  2016年   174篇
  2015年   215篇
  2014年   254篇
  2013年   325篇
  2012年   509篇
  2011年   477篇
  2010年   257篇
  2009年   231篇
  2008年   283篇
  2007年   254篇
  2006年   246篇
  2005年   210篇
  2004年   173篇
  2003年   125篇
  2002年   101篇
  2001年   42篇
  2000年   41篇
  1999年   30篇
  1998年   22篇
  1997年   13篇
  1996年   18篇
  1995年   19篇
  1994年   13篇
  1993年   14篇
  1992年   33篇
  1991年   27篇
  1990年   34篇
  1989年   32篇
  1988年   28篇
  1987年   26篇
  1986年   18篇
  1985年   16篇
  1984年   14篇
  1983年   15篇
  1982年   7篇
  1981年   10篇
  1980年   9篇
  1979年   13篇
  1977年   10篇
  1975年   9篇
  1974年   15篇
  1973年   9篇
  1972年   9篇
排序方式: 共有5725条查询结果,搜索用时 31 毫秒
41.
42.
43.
Controlled donation after circulatory death (cDCD) is used for “extended criteria” donors with poorer kidney transplant outcomes. The French cDCD program started in 2015 and is characterized by normothermic regional perfusion, hypothermic machine perfusion, and short cold ischemia time. We compared the outcomes of kidney transplantation from cDCD and brain-dead (DBD) donors, matching cDCD and DBD kidney transplants by propensity scoring for donor and recipient characteristics. The matching process retained 442 of 499 cDCD and 809 of 6185 DBD transplantations. The DGF rate was 20% in cDCD recipients compared with 28% in DBD recipients (adjusted relative risk [aRR], 1.43; 95% confidence interval [CI] 1.12–1.82). When DBD transplants were ranked by cold ischemia time and machine perfusion use and compared with cDCD transplants, the aRR of DGF was higher for DBD transplants without machine perfusion, regardless of the cold ischemia time (aRR with cold ischemia time <18 h, 1.57; 95% CI 1.20–2.03, vs aRR with cold ischemia time ≥18 h, 1.79; 95% CI 1.31–2.44). The 1-year graft survival rate was similar in both groups. Early outcome was better for kidney transplants from cDCD than from matched DBD transplants with this French protocol.  相似文献   
44.
Belatacept may increase cytomegalovirus (CMV) disease risk after conversion from CNI-based therapy. We analyzed CMV disease characteristics after belatacept conversion. Propensity score matching was used to compare CMV disease incidence in belatacept- and CNI-treated kidney transplant recipients (KTRs). CMV disease characteristics and risk factors under belatacept were analyzed. In total, 223 KTRs (median age [IQR] 59.2 years [45.4–68.5]) were converted to belatacept (median of 11.5 months [2.5–37.0] post-transplantation); 40/223 (17.9%) developed CMV disease. Independent risk factors included increased age (p = .0164), D+/R− CMV serostatus (p = .0220), and low eGFR at conversion (p = .0355). Among 181 belatacept-treated patients matched to 181 controls, 32/181 (17.7%) experienced CMV disease (vs. 5/181 controls [2.8%]). CMV disease cumulative incidences were 6.33 and 0.91/100 person-years (p-y) in belatacept and control groups, respectively. CMV disease risk was particularly high in elderly patients (converted >70 years) and those with eGFR <30 ml/min; cumulative incidences were 18.4 and 5.2/100 p-y, respectively. CMV diseases under belatacept were atypical, with late-onset disease (24/40 patients [60%]), high CMV seropositivity (27/40, 67%), increased severe and tissue-invasive disease rates (gastrointestinal involvement in 32/40 [80%]) and life-threatening diseases (4/40 [10%]). These findings should stimulate further research to secure the use of belatacept as a valuable rescue therapy in KTRs.  相似文献   
45.
Quality of Life Research - The Adult Social Care Outcomes Toolkit for Carers (ASCOT-Carer), developed in England, measures the effects of long-term care (LTC) services and carer support on informal...  相似文献   
46.
Background

Colorectal cancer (CRC) has a high incidence worldwide, especially in high-income countries. In France, a national CRC screening program targeting residents aged 50–74 years has been in place since 2009. Little is known about CRC screening practices in cancer survivors, even though some have an increased risk of developing a second cancer in the colorectum. This study aims to identify the barriers to CRC screening among cancer survivors.

Methods

This cross-sectional study based on the French national VICAN survey included individuals diagnosed in 2010 with a cancer in 1 of 11 locations other than the colorectum and interviewed 5 years after diagnosis about various health-related issues. Binary logistic regression was used to identify the factors associated with lack of up-to-date CRC screening in cancer survivors without cancer progression.

Results

Of the 2935 cancer survivors included in the study, 35.3% reported undergoing a screening test in the previous 2 years. The rate of up-to-date CRC screening rose to 49.3% in survivors aged 51–75 years. Among these, lack of CRC screening in the recommended time frame was associated with obesity, current smoking, non-use of complementary medicine, perceived financial difficulties, and poor access to general practitioners.

Conclusions

Barriers to CRC screening can be personal and/or institutional.

  相似文献   
47.
In order to study the biomechanical properties of the arterial wall and to compare arteries with different histologic structures, we designed a device that allows testing of arterial segments under near-physiologic conditions. A hydrodynamic generator simulates systolo-diastolic pressures in an open loop. An intraarterial pressure sensor and a sonomicrometer connected to two piezoelectric crystals placed in diametric opposition on the arterial wall allow computer calculation of compliance, stiffness, midwall radial arterial stress, Young modulus, and incremental modulus for a given arterial segment at a given pressure setting. Seven healthy common carotid artery (CCA) segments and seven healthy (superficial) femoral artery (FA) segments were studied immediately after removal from brain-dead donors between the ages of 18 and 35 years. Histologic examination was performed to determine the density of elastic fibers in the arterial wall. Hysteresis was observed in all segments regardless of pressure settings. Compliance was greater and modulus values and stiffness were lower in CCA than in FA. No evidence of structural change was noted after testing in the circulation loop. These preliminary results open the way to a wide variety of applications for our hydrodynamic circulation loop. Experiments will be undertaken to compare the mechanical properties of arteries before and after cryopreservation.
Propriétés visco-élastiques des artères humaines. Méthodologie et résultats préliminaires
Résumé Dans le but d'étudier les propriétés mécaniques de la paroi artérielle et de pouvoir établir des comparaisons entre des segments artériels de structure histologique différente, nous avons mis au point un banc d'essai hydrodynamique permettant de tester des segments artériels dans des conditions voisines de la réalité physiologique. Un générateur hydrodynamique permettait d'obtenir dans un circuit ouvert un régime de pressions de type systolo-diastolique. Un capteur de pression intra-artériel, ainsi qu'un sonomicromètre relié à des cristaux piézo-électriques placés de façon diamétralement opposée sur la paroi artérielle, permettaient de calculer, pour un régime de pressions donné et grâce à l'acquisition de données dans un système informatique, la compliance, la rigidité, la contrainte trans-pariétale, le module de Young, le module incrémentiel d'un segment artériel. Nous avons étudié sept artères carotides communes (CC), et sept artères fémorales (superficielles) (F) fraîchement prélevées chez des sujets sains âgés de 18 à 35 ans. Des corrélations avec la richesse en fibres élastiques de la paroi artérielle ont été établies. Nous avons mis en évidence un phénomène d'hystérésis pour chaque artère testée quel que soit le niveau de pression considéré. La compliance des artères CC a été plus importante, les modules et la rigidité ont été moins importants et ce de façon significative par rapport aux artères F. Aucune altération histologique n'a été mise en évidence après passage des segments artériels au banc d'essai. Ces résultas préliminaires nous permettent d'envisager de nombreuses applications à ce travail dont l'une d'entre elles sera la mesure comparative des propriétés mécaniques des artères avant et après cryopréservation.
  相似文献   
48.
Pain in the lesser metatarsophalangeal area of the foot remains a diagnostic challenge. This pathology often is attributed to neuromas. These painful lesions, although predisposed to this area, are not nearly as common as they are thought to be. The "systems approach" to diagnosis can be extremely helpful in establishing an accurate cause and subsequent proper diagnosis of lesser metatarsophalangeal joint pain.  相似文献   
49.
Evidence about the long-term persistence of the booster-mediated immunity against Omicron is mandatory for pandemic management and deployment of vaccination strategies. A total of 155 healthcare professionals (104 COVID-19 naive and 51 with a history of SARS-CoV-2 infection) received a homologous BNT162b2 booster. Binding antibodies against the spike protein and neutralizing antibodies against Omicron were measured at several time points before and up to 6 months after the booster. Geometric mean titers of measured antibodies were correlated to vaccine efficacy (VE) against symptomatic disease. Compared to the highest response, a significant 10.2- and 11.5-fold decrease in neutralizing titers was observed after 6 months in participants with and without history of SARS-CoV-2 infection. A corresponding 2.5- and 2.9-fold decrease in binding antibodies was observed. The estimated T1/2 of neutralizing antibodies in participants with and without history of SARS-CoV-2 infection was 42 (95% confidence interval [CI]: 25–137) and 36 days (95% CI: 25–65). Estimated T1/2 were longer for binding antibodies: 168 (95% CI: 116–303) and 139 days (95% CI: 113–180), respectively. Both binding and neutralizing antibodies were strongly correlated to VE (r = 0.83 and 0.89). However, binding and neutralizing antibodies were modestly correlated, and a high proportion of subjects (36.7%) with high binding antibody titers (i.e., >8434 BAU/ml) did not have neutralizing activity. A considerable decay of the humoral response was observed 6 months after the booster, and was strongly correlated with VE. Our study also shows that commercial assays available in clinical laboratories might require adaptation to better predict neutralization in the Omicron era.  相似文献   
50.
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