首页 | 官方网站   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   1291篇
  免费   121篇
  国内免费   4篇
医药卫生   1416篇
  2023年   27篇
  2022年   69篇
  2021年   108篇
  2020年   35篇
  2019年   48篇
  2018年   38篇
  2017年   34篇
  2016年   47篇
  2015年   48篇
  2014年   50篇
  2013年   52篇
  2012年   89篇
  2011年   101篇
  2010年   55篇
  2009年   57篇
  2008年   87篇
  2007年   72篇
  2006年   79篇
  2005年   68篇
  2004年   64篇
  2003年   41篇
  2002年   52篇
  2001年   9篇
  2000年   5篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   3篇
  1994年   2篇
  1993年   4篇
  1991年   4篇
  1989年   2篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1984年   4篇
  1983年   4篇
  1982年   2篇
  1981年   4篇
  1979年   3篇
  1976年   2篇
  1975年   2篇
  1974年   3篇
  1973年   3篇
  1971年   7篇
  1970年   2篇
  1967年   2篇
  1966年   2篇
  1964年   2篇
  1959年   1篇
排序方式: 共有1416条查询结果,搜索用时 15 毫秒
1.
Multiple tools have been developed to assist nurses and other care providers to identify and quantify pressure ulcer risk. One of the most widely used tools is the Braden Scale for Predicting Pressure Ulcer Risk. It has been in use for 2 decades and multiple studies have individually reported on its reliability and validity. This article summarizes the reliability and validity of the instrument, and discusses implications for its use in clinical and research settings. The Braden Scale for Predicting Pressure Ulcer Risk has generally performed well in the clinical setting. It has demonstrated reliability and validity in multiple clinical settings, and its parsimonious format enhances incorporation into routine clinical practice. Expanding the instrument may further increase its reliability and validity in the research setting.  相似文献   
2.
Periods of reduced joint loading have been shown to induce changes in the biochemical composition. metabolism and mechanics of articular cartilage. In this study, changes in cartilage swelling behavior were studied following a 4-week period of joint immobilization, using a recently developed osmotic loading technique [J. Biomech, 32 (1999) 401-408]. The magnitude and distribution of swelling strains were measured in cartilage-bone samples equilibrated in physiological and hypotonic saline, relative to a hypertonic reference NaCl solution. Physicochemical parameters (glycosaminoglycan fixed charge density and water volume fraction) were determined in site-matched cartilage samples. The experimental data for swelling strains, fixed charge density and water volume fraction were used with a triphasic mechano-chemical theory [J. Biomech. Eng. 113 (1991) 245-258] to determine the effect of joint immobilization on the tensile modulus of the cartilage solid matrix. Four weeks of immobilization resulted in a significant increase in the magnitude of swelling-induced strains, and a significant decrease in fixed charge density in cartilage, as compared with the contralateral controls. Joint immobilization also resulted in decreases in values for the modulus of cartilage, as compared with the contralateral controls. Our results suggest that 4 weeks of joint immobilization had a significant effect on cartilage mechanical function that may be linked to collagen changes in the cartilage extracellular matrix.  相似文献   
3.
An electron microscopic study of kitten kidney cells infected with a feline calicivirus (a member of the family Picornaviridae) has been carried out. Although cells appeared to be synchronised by the light microscope, electron microscopic changes were extremely variable. The first observable and consistent changes occurred in the nucleus followed by the formation of membrane bound vesicles in the cytoplasm. A variety of arrangements of virus particle accumulation were observed in infected cells. These included crystalline arrays, membranous cisternae and accumulation of particles in fine fibrillar material. The finding of accumulations of virus particles in association with smooth membranes is of importance in respect of the recent biochemical evidence of poliovirus assembly in relation to smooth membranes.  相似文献   
4.
5.
6.
The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo‐vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel–Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro‐caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X‐ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family‐based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico‐thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240‐4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo‐axoidal malformation compromising spinal cord integrity. This distinctive mutation‐specific pattern of malformation differs from Klippel–Feil syndrome and broadens the current classification, defining a sub‐type of RIPPLY2‐related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo‐auriculo‐vertebral spectrum disorder.  相似文献   
7.
Most patients with hypertrophic cardiomyopathy and congenital heart diseases express the atrial essential myosin light chains (ALC-1) in their ventricles, partially replacing the ventricular essential light chains (VLC-1). This VLC-1/ALC-1 isoform shift is correlated with an increase in cross-bridge cycling kinetics as measured using skinned fibers from the hypertrophied ventricles of human hearts.To study the functional importance of hALC-1 in the intact perfused heart, we generated a transgenic rat model (TGR) overexpressing hALC-1 in the heart. Twelve-week-old TGR rats expressed 17±4 g hALC-1 per mg of whole SDS-soluble protein. Their perfused heart contractility parameters were evaluated using the Langendorff preparation. Expression of hALC-1 was accompanied by statistically significant improvements (P<0.001) in the contractile parameters of the hearts of the TGR compared to the age matched control (WKY) animals, represented by increases from 20.8±2.3 to 45.1±3.6 mmHg/g heart weight in the developed left ventricular pressure, 1,035.7±89.8 to 2,181±135.4 mmHg/s in the contraction rate, and 713±60.2 to 1,364±137.4 mmHg/s in the relaxation rate in the WKY and the TGR groups respectively. Characterizing the functional effects of hALC-1 at the whole organ level represents a step towards gene therapy of heart failure.  相似文献   
8.
Objectifying donor lung quality is difficult and currently there is no consensus. Several donor scoring systems have been proposed in recent years. They all lack large-scale external validation and widespread acceptance. A retrospective evaluation of 2201 donor lungs offered to the lung transplant program at the Medical University of Vienna between January 2010 and June 2018 was performed. Five different lung donor scores were calculated for each offer (Oto, ET, MALT, UMN-DLQI, and ODSS). Prediction of organ utilization, 1-year graft survival, and long-term outcome were analyzed for each score. 1049 organs were rejected at the initial offer (group I), 209 lungs declined after procurement (group II), and 841 lungs accepted and transplanted (group III). The Oto score was superior in predicting acceptance of the initial offer (AUC: 0.795; CI: 0.776–0.815) and actual donor utilization (AUC: 0.660; CI: 0.618–0.701). Prediction of 1-year graft survival was best using the MALT score, Oto score, and UMN-DLQI. Stratification of early outcome by MALT was significant for length of mechanical ventilation (LMV), PGD3 rates, ICU stay and hospital stay, and in-hospital-mortality, respectively. To the best of our knowledge, this study is the largest validation analysis comparing currently available donor scores. The Oto score was superior in predicting organ utilization, and MALT score and UMN-DLQI for predicting outcome after lung transplantation.  相似文献   
9.
10.
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-23

京公网安备 11010802026262号