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   5757篇
  免费   491篇
  国内免费   9篇
耳鼻咽喉   48篇
儿科学   135篇
妇产科学   136篇
基础医学   802篇
口腔科学   249篇
临床医学   700篇
内科学   1133篇
皮肤病学   53篇
神经病学   384篇
特种医学   430篇
外科学   635篇
综合类   120篇
一般理论   7篇
预防医学   576篇
眼科学   40篇
药学   455篇
  1篇
中国医学   16篇
肿瘤学   337篇
  2021年   80篇
  2020年   57篇
  2019年   78篇
  2018年   90篇
  2017年   77篇
  2016年   79篇
  2015年   94篇
  2014年   111篇
  2013年   154篇
  2012年   253篇
  2011年   275篇
  2010年   147篇
  2009年   140篇
  2008年   228篇
  2007年   226篇
  2006年   268篇
  2005年   228篇
  2004年   213篇
  2003年   178篇
  2002年   188篇
  2001年   180篇
  2000年   195篇
  1999年   132篇
  1998年   104篇
  1997年   93篇
  1996年   81篇
  1995年   106篇
  1994年   93篇
  1993年   87篇
  1992年   114篇
  1991年   127篇
  1990年   115篇
  1989年   121篇
  1988年   80篇
  1987年   115篇
  1986年   133篇
  1985年   102篇
  1984年   82篇
  1983年   76篇
  1982年   54篇
  1981年   52篇
  1980年   42篇
  1979年   71篇
  1978年   60篇
  1977年   57篇
  1976年   46篇
  1975年   53篇
  1974年   48篇
  1972年   45篇
  1969年   41篇
排序方式: 共有6257条查询结果,搜索用时 0 毫秒
991.
Glucose moves into airway secretions after a glucose load. Therefore people with diabetes or hyperglycemia spend a significant proportion of each day with glucose in their airways secretions. This study investigated the effects of glucose on isolated human airways and on cultured airway smooth muscle (ASM) cells. Human isolated bronchi were stimulated with acetylcholine, histamine, and transmural stimulation and treated with the selective ROCK inhibitors Y27632 and SB772077B under high-glucose conditions. The effect of high glucose concentrations on intracellular calcium flux and the phosphorylation of MYPT1 in ASM cells was also investigated. High (44 mM for 6 h) glucose, but not mannitol, concentrations led to an enhanced responsiveness of ASM to contractile agents. Y27632 and SB772077B completely abolished (P < 0.05) the enhanced contractile effects with a high-concentration glucose solution, compared with control tissues. In cultured ASM cells, incubation with high glucose concentrations significantly (P < 0.05) enhanced bradykinin-induced intracellular calcium flux and the levels of pMYPT1, which were inhibited by Y27632 (P < 0.05). Our study has demonstrated that high glucose concentrations leads to hyperresponsiveness of human isolated bronchi and enhances intracellular calcium release in cultured ASM cells via a Rho/ROCK- and pMYPT1-dependent pathway, suggesting that this crucial pathway may contribute to the reduced lung function observed in patients with diabetes. These data propose novel targets for the treatment of patients with respiratory diseases that also suffer from diabetes mellitus.  相似文献   
992.
993.
The objective of this study was to implement and evaluate the performance of a biplane correlation imaging (BCI) technique aimed to reduce the effect of anatomic noise and improve the detection of lung nodules in chest radiographs. Seventy-one low-dose posterior–anterior images were acquired from an anthropomorphic chest phantom with 0.28° angular separations over a range of ±10° along the vertical axis within an 11 s interval. Similar data were acquired from 19 human subjects with institutional review board approval and informed consent. The data were incorporated into a computer-aided detection (CAD) algorithm in which suspect lesions were identified by examining the geometrical correlation of the detected signals that remained relatively constant against variable anatomic backgrounds. The data were analyzed to determine the effect of angular separation, and the overall sensitivity and false-positives for lung nodule detection. The best performance was achieved for angular separations of the projection pairs greater than 5°. Within that range, the technique provided an order of magnitude decrease in the number of false-positive reports when compared with CAD analysis of single-view images. Overall, the technique yielded ~1.1 false-positive per patient with an average sensitivity of 75%. The results indicated that the incorporation of angular information can offer a reduction in the number of false-positives without a notable reduction in sensitivity. The findings suggest that the BCI technique has the potential for clinical implementation as a cost-effective technique to improve the detection of subtle lung nodules with lowered rate of false-positives.  相似文献   
994.
Neurosurgeons use ventricular veins during an endoscopic third ventriculocisternostomy as landmark to progress in ventricles. In the current literature, there is lack of detailed intraventricular venous anatomy. Majority of those papers treats Monro’s foramen venous variations. There are no data of third ventricle venous anatomy and variations in the literature. We reported two cases of unusual interthalamic vein that we need to spare during endoscopy.  相似文献   
995.
Rubin GJ  Amlôt R  Page L 《Health physics》2011,101(5):545-550
Public responses to large-scale radiological incidents are often thought to be disproportionate to the objective risk and can involve widespread societal disruption. Recent experiences of the (200)Po incident in central London suggest that public responses depend heavily on the nature of the incident and the effectiveness of risk communication efforts. This paper describes the outcome of several studies done in the aftermath of the (200)Po incident that suggest the reaction of the public on this occasion was muted, even for those directly affected. However, the desire for accurate, up-to-date and individually-tailored information was strong, and satisfaction with the efforts of the responding agencies was mediated by this information provision. A small minority of individuals was difficult to reassure effectively. This group may confer a particular drain on resources. Lessons for the risk communication efforts of public health responders are identified, in particular the importance of helping individuals to identify their risk of exposure, understand the difference between acute and chronic effects of exposure, and appreciate the meaning of any test results. Attempts at providing reassurance in the absence of specific information are likely to be counterproductive in any future radiological incident.  相似文献   
996.
Despite the targeting of traditional risk factors for cardiovascular disease, disease burden has not been completely eliminated. Thiamine is an essential cofactor in carbohydrate metabolism and individuals with diabetes are thiamine deficient. The pathophysiology of recognised complications of thiamine deficiency is similar to that underlying atherosclerosis and the metabolic syndrome, namely oxidative stress, inflammation and endothelial dysfunction. This review examines the mechanisms by which thiamine deficiency occurs in individuals with diabetes, how this deficiency leads to hyperglycaemic-induced damage, and the effect of thiamine replacement on vascular disease, endothelial function and oxidative stress. Thiamine administration can prevent the formation of harmful by-products of glucose metabolism, reduce oxidative stress and improve endothelial function. The potential benefit of long-term replacement in those with diabetes is not yet known but may reduce cardiovascular risk and angiopathic complications.  相似文献   
997.
Cardiovascular disease is the number one cause of death for women. In an effort to reduce cardiovascular burden for women, identifying risk factors and increasing awareness of sex differences are fundamental. This systematic review examines cardiovascular disease risk for women. A search of the literature was undertaken using key health databases. Search terms used were cardiovascular disease AND women OR gender. Additional references were manually identified from this literature; 58 articles were reviewed in total. On average, cardiovascular disease presents 10 years later in women compared to men. By this time, they are more likely to suffer from more comorbidities, placing them at higher risk. The complexity of cardiovascular disease identification in women is accentuated through atypical symptoms, and has the potential to lead to delayed and/or misdiagnosis. It is clear through identifying sex differentiation in cardiovascular risk factors that there has been an increased awareness of symptom presentation for women. In light of the sex differences in risk factors, sex‐specific aspects should be more intensively considered in research/practice to improve clinical outcomes for female cardiovascular disease patients.  相似文献   
998.
999.
目的:分析载脂蛋白B(apoB)基因EcoRI、XbaI、MspI位点和载脂蛋白AI(apoAI)基因-75bp、+83bp位点多态性与哈萨克族人冠心病的关系.方法:采用聚合酶链式反应-限制性片段长度多态性分析法检测185例哈萨克族冠心病患者和216例哈萨克族非冠心病对照者的这些位点多态性.结果:①TC、TG及apoA...  相似文献   
1000.

Introduction

As a result of neurophysiological injury, stroke patients have mobility limitations, mainly on the side of the body contralateral to the lesioned hemisphere. The purpose of this study is to quantify motor compensation strategies in stroke patients during the activity of drinking water from a glass.

Material and methods

Four male patient with cerebrovascular disease and four right-handed, healthy male control subjects. The motion analysis was conducted using the Vicon Motion System® and surface electromyography equipment ZeroWire Aurion®. We analysed elbow, shoulder and trunk joint movements and performed a qualitative analysis of the sequence of muscle activation.

Results

Trunk, shoulder and elbow movements measured in the stroke patient along the sagittal plane decreased during the drinking from a glass activity, while the movements in the shoulder in the coronal plane and trunk increased. As for the sequence of muscle activation, anterior, middle and posterior deltoid all contracted in the patient group during the task, while the upper trapezius activation remained throughout the activity.

Conclusions

Quantitative analysis of movement provides quantitative information on compensation strategies used by stroke patients, and is therefore, clinically relevant.  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