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   2518篇
  免费   179篇
  国内免费   17篇
耳鼻咽喉   12篇
儿科学   72篇
妇产科学   63篇
基础医学   419篇
口腔科学   17篇
临床医学   263篇
内科学   538篇
皮肤病学   38篇
神经病学   251篇
特种医学   44篇
外科学   315篇
综合类   24篇
一般理论   3篇
预防医学   209篇
眼科学   76篇
药学   183篇
中国医学   12篇
肿瘤学   175篇
  2023年   9篇
  2022年   43篇
  2021年   56篇
  2020年   35篇
  2019年   68篇
  2018年   64篇
  2017年   58篇
  2016年   43篇
  2015年   45篇
  2014年   77篇
  2013年   117篇
  2012年   174篇
  2011年   167篇
  2010年   94篇
  2009年   93篇
  2008年   158篇
  2007年   192篇
  2006年   170篇
  2005年   158篇
  2004年   165篇
  2003年   135篇
  2002年   162篇
  2001年   22篇
  2000年   22篇
  1999年   17篇
  1998年   23篇
  1997年   21篇
  1996年   13篇
  1995年   16篇
  1994年   10篇
  1993年   11篇
  1992年   15篇
  1991年   12篇
  1990年   11篇
  1989年   7篇
  1988年   12篇
  1987年   15篇
  1985年   13篇
  1984年   7篇
  1983年   6篇
  1982年   7篇
  1981年   19篇
  1980年   11篇
  1979年   9篇
  1978年   11篇
  1976年   6篇
  1974年   8篇
  1973年   9篇
  1972年   6篇
  1958年   6篇
排序方式: 共有2714条查询结果,搜索用时 31 毫秒
71.

Background

Visual scanning and planning of actions are reported to be abnormal in patients with schizophrenia. Most studies that monitored eye movements in these patients were performed under free-viewing conditions and used 2-dimensional images. However, images differ from the natural world in several ways, including task demands and the dimensionality of the display. Our study was designed to assess whether abnormalities in visual exploration in patients with schizophrenia generalize to active-viewing tasks in realistic conditions of viewing and to examine whether disturbances in action sequencing in these patients are reflected in their visual scanning patterns while executing natural tasks.

Methods

We monitored visual scan paths in patients with schizophrenia and healthy controls. Participants performed several tasks in which they were asked to look at a realistic scene on a table (free-viewing) and perform 2 active-viewing tasks: a familiar task (sandwich-making) and an unfamiliar task (model-building). The scenes contained both task-relevant and task-irrelevant objects.

Results

We included 15 patients and 15 controls in our analysis. Patients exhibited abnormalities in the free-viewing condition. Their patterns of exploration were similar to those of controls in the familiar task, but they showed scanning differences in the unfamiliar task. Patients were also slower than controls to accomplish both tasks.

Limitations

Patients with schizophrenia were taking antipsychotic medications, so the presence of medication effects cannot be excluded.

Conclusion

People with schizophrenia present a basic psycho-motor slowing and seem to establish a less efficient planning strategy in the case of more complex and unfamiliar tasks.  相似文献   
72.

Objectives

Several epidemiological studies have revealed the co-occurrence of other autoimmune diseases (AIDs) within patients with systemic sclerosis (SSc). However, some of these studies were based on small cohorts and wide ranges of prevalence have been reported. Therefore to overcome these limitations of individual studies, we sought to perform a meta-analysis to determine the accurate prevalence of polyautoimmunity in SSc.

Methods

We performed a systematic review and a meta-analysis of literature in MEDLINE and Embase databases from January 1960 to March 2013. All cohort studies reporting on prevalence of other AIDs known to be associated with SSc were analyzed. Prevalence of polyautoimmunity and of each AID were then calculated.

Results

Ten studies reporting polyautoimmunity were identified corresponding to a total of 6102 SSc patients. Overall 1432 patients with at least one AID were identified corresponding to a weighted prevalence of polyautoimmunity equal to 25.7% CI 95% [20.1%–31.6%]. Overall 208/5139 SSc-patients had at least two additional AIDs resulting in a weighted prevalence of 3.9% [3.3%–4.4%]. The most prevalent associated AIDs were autoimmune thyroid disease (10.4%) followed by Sjögren's syndrome (7.7%) and dermatopolymyositis/polymyositis (5.6%).

Conclusion

Our results confirm that SSc polyautoimmunity is a frequent condition in SSc affecting a quarter of SSc-patients. The impact on the phenotype and also on the management and therapy will need to be addressed now in further works.  相似文献   
73.
74.
75.

Background

Malabsorptive surgical procedures lead to deficiencies in fat-soluble vitamins. However, results concerning serum vitamin D (25OHD) after gastric bypass (GBP) are controversial. The aim of the study was to assess the influence of GBP on 25OHD and calcium metabolism.

Methods

Parameters of calcium metabolism were evaluated in 202 obese subjects before and 6 months after GBP. Thirty of them were matched for age, gender, weight, skin color, and season with 30 subjects who underwent sleeve gastrectomy (SG). A multivitamin preparation that provides 200 to 500 IU vitamin D3 per day was systematically prescribed after surgery.

Results

In the 202 patients after GBP, serum 25OHD significantly increased from 13.4?±?9.1 to 22.8?±?11.3 ng/ml (p?<?0.0001), whereas parathyroid hormone (PTH) did not change. Despite a decrease in calcium intake (p?<?0.0001) and urinary calcium/creatinine ratio (p?=?0.015), serum calcium increased after GBP (p?<?0.0001). Preoperatively, 91 % of patients had 25OHD insufficiency (<30 ng/ml), 80 % deficiency (<20 ng/ml), and 19 % secondary hyperparathyroidism (>65 pg/ml) vs. 76, 44, and 17 %, respectively, following GBP. Serum 25OHD was negatively correlated with BMI at 6 months after GBP (R?=??0.299, p?<?0.0001). In the two groups of 30 subjects, serum 25OHD and PTH did not differ at 6 months after GBP or SG.

Conclusions

At 6 months after GBP, serum 25OHD significantly increased in subjects supplemented with multivitamins containing low doses of vitamin D. These data suggest that weight loss at 6 months after surgery has a greater influence on vitamin D status than malabsorption induced by GBP.  相似文献   
76.
77.
Vasculopathy, immunological abnormalities, and fibrosis are the key features in the pathogenesis of systemic sclerosis (SSc). Expression of each of the three pathologic features varies among SSc patients leading to disease heterogeneity and variable organ manifestations. Although the etiology of SSc has not yet been fully elucidated, a growing body of evidence suggests that extracellular matrix overproduction by activated fibroblasts results from a complex interplay between endothelial cells, immune cells and fibroblasts through cell–cell and cell–matrix interactions and communications. Relevant animal models are essential tools to in-depth investigate pathogenesis of SSc. Several murine and avian models are available; however, some models display inflammation followed by fibrosis, whether some others primarily mimic autonomous fibroblast activation. In addition, typical microvascular changes of SSc are only observed in few models. Therefore, none of these animal models encompasses all features of the human disease and a critical selection is mandatory for successful in vivo studies. Hence, we will provide an overview of the most important experimental models of dermal fibrosis and SSc and discuss their respective contribution to the better understanding of SSc pathogenesis.  相似文献   
78.
79.
BackgroundThe prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients has increased and MRSA seems to be associated with a poorer prognosis. The aim of this study was to assess the prevalence and clinical consequences of MRSA and methicillin-susceptible Staphylococcus aureus (MSSA), associated or not associated with Pseudomonas aeruginosa (PA).MethodsIn a retrospective study on 419 sputum producer patients (293 adults and 126 children > 7 years of age), we recorded patient characteristics, lung function, nutritional status, IV antibiotics and hospitalisations, the presence of SA and/or PA and FEV1 decline over 2 years.ResultsSA was found in 72% of the patients: MSSA in 68.2% of children and 48.8% of adults; MRSA in 17.5% of children and 17.8% of adults. Sixty percent of MRSA patients and 60.4% of MSSA patients also harboured PA. The rate of deterioration of clinical status of the various groups, as assessed from respiratory function, IV antibiotic courses and hospitalisations, increased in the order: no SA/no PA, MSSA alone, MRSA alone, MSSA/PA, MRSA/PA, and PA alone. Nutritional status did not differ between groups. Results were roughly similar for children and adults. The yearly FEV1 decline was significantly higher only for MRSA/PA patients (p = 0.03) compared to no SA/no PA patients.ConclusionClinical condition of CF patients with MSSA only or MRSA only appeared similar, whereas MRSA/PA patients had more severe respiratory function than MSSA/PA patients. In CF patients, MRSA might be more deleterious than MSSA only when associated with PA.  相似文献   
80.
Walker's comprehensive review of claims of gender difference and gender bias in moral cognition concluded 1) that gender explains a negligible amount of the variability in moral reasoning development, 2) that accumulated evidence does not support claims of gender polarity in moral orientations (i.e., an ethic of care and an ethic of justice), and 3) that future research should focus on the range of psychological processes that engender moral maturity. This study examined whether male and female predoctoral dental students who completed an ethics curriculum grounded in Rest's comprehensive model of moral functioning differed on measures of four capacities: moral sensitivity, moral reasoning, moral motivation, and moral implementation. From archival data at the University of Minnesota School of Dentistry, data on sixty females and sixty males were randomly selected from five cohorts (n=386) who completed an ethics curriculum and outcome measures of the four capacities between 1996 and 2000. Gender differences were not apparent for a measure of moral sensitivity, but were evident for one of the moral reasoning indices, for the responsibility dimension of moral motivation, and for the measure of moral implementation. Implications are drawn for future research and for professional ethics education.  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