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   1081篇
  免费   64篇
  国内免费   7篇
耳鼻咽喉   26篇
儿科学   13篇
妇产科学   40篇
基础医学   143篇
口腔科学   51篇
临床医学   91篇
内科学   360篇
皮肤病学   10篇
神经病学   54篇
特种医学   22篇
外科学   117篇
综合类   6篇
一般理论   1篇
预防医学   61篇
眼科学   9篇
药学   65篇
肿瘤学   83篇
  2023年   8篇
  2022年   36篇
  2021年   71篇
  2020年   27篇
  2019年   29篇
  2018年   41篇
  2017年   40篇
  2016年   25篇
  2015年   42篇
  2014年   53篇
  2013年   46篇
  2012年   92篇
  2011年   92篇
  2010年   44篇
  2009年   45篇
  2008年   67篇
  2007年   71篇
  2006年   55篇
  2005年   53篇
  2004年   42篇
  2003年   29篇
  2002年   18篇
  2001年   7篇
  2000年   7篇
  1999年   6篇
  1994年   3篇
  1993年   2篇
  1992年   6篇
  1991年   3篇
  1990年   6篇
  1989年   6篇
  1988年   10篇
  1987年   2篇
  1986年   6篇
  1985年   7篇
  1984年   3篇
  1983年   3篇
  1981年   2篇
  1979年   5篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1974年   4篇
  1973年   5篇
  1970年   8篇
  1969年   2篇
  1968年   3篇
  1966年   2篇
  1964年   1篇
  1963年   1篇
排序方式: 共有1152条查询结果,搜索用时 15 毫秒
51.
52.
Human beings often observe other people's social interactions without being a part of them. Whereas the implications of some brain regions (e.g. amygdala) have been extensively examined, the implication of the precuneus remains yet to be determined. Here we examined the implication of the precuneus in third‐person perspective of social interaction using functional magnetic resonance imaging (fMRI). Participants performed a socially irrelevant task while watching the biological motion of two agents acting in either typical (congruent to social conventions) or atypical (incongruent to social conventions) ways. When compared to typical displays, the atypical displays elicited greater activation in the central and posterior bilateral precuneus, and in frontoparietal and occipital regions. Whereas the right precuneus responded with greater activation also to upside down than upright displays, the left precuneus did not. Correlations and effective connectivity analysis added consistent evidence of an interhemispheric asymmetry between the right and left precuneus. These findings suggest that the precuneus reacts to violations of social expectations, and plays a crucial role in third‐person perspective of others' interaction even when the social context is unattended. Hum Brain Mapp 35:5190–5203, 2014. © 2014 Wiley Periodicals, Inc .  相似文献   
53.
Although in apoE/LDLR(-/-) mice atherosclerotic plaques develop spontaneously, various atherogenic diets (e.g. Western diet) are frequently used to accelerate the disease in this model. The objective of this study was to compare the effects on atherosclerosis of Western diet and other types of high-fat, high cholesterol, hypertriglyceridemic diets with the effects of the low carbohydrate, high protein (LCHP) diet. 16-18 week old mice with pre-established atherosclerosis were assigned to experimental groups and fed for the next 10 weeks with control diet, margarine diet (margarine 7%), hypertrigliceridemic diet (fructose 62%), high-fat diet (Western diet), high cholesterol diet (egg yolk diet) or with LCHP diet. No differences in body weight were observed among experimental groups. Plasma cholesterol concentration was significantly increased in egg yolk diet- and LCHP diet-fed apoE/LDLR(-/-) mice as compared to other types of diets. Plasma concentration of triacylglycerols was significantly elevated in egg yolk diet- and LCHP diet-fed apoE/LDLR(-/-) mice. The area of atherosclerotic plaques in the aortic root was substantially increased in LCHP diet-fed mice as compared to other types of diets. Furthermore, in brachiocephalic arteries of LCHP diet-fed mice there was evidence of plaque rupture. In conclusion, the LCHP diet promoted atherosclerosis in apoE/LDLR(-/-) mice more intensively than classical Western diet and favored the development of unstable lesions.  相似文献   
54.
A combination of crash cushion and end-terminal, hybrid energy absorbing devices have been in use worldwide for a few years already. They include SafeEnd, a system Poland has recently introduced. Some road authorities have raised concerns as regards the operating conditions of the devices and how they work together with safety barriers. The objective of this research is to clarify the concerns and answer the following questions: (1) Can SafeEnd devices be used as hybrid devices and combine the roles of end-terminal and crash cushion placed before an obstacle? (2) What should be the rules for installing crash cushions at diverging roads and at the start of an off-ramp? The article presents characteristics of SafeEnd devices, defines the doubts raised by road safety auditors, discusses the results of field and numerical tests of the devices and explains the design principles for interchange ramps where crash cushions are required. The study results have helped to answer the research questions: SafeEnd devices fulfil the role of end-terminal and crash cushion, it is possible to make them more visible and principles have been defined for how the devices should be used at road interchanges. Further research should help to define general principles of deploying road restraint systems such as crashworthy terminals, crash cushions or hybrid devices.  相似文献   
55.
The interfacial polycondensation of titanium dioxide was studied at the bare and fiberglass membrane supported polarized liquid–liquid interface (LLI). Titanium dioxide synthesis was derived from the titanium (IV) tetrabutoxide (initially dissolved in the 1,2-dichloroethane) interfacial hydrolysis followed by its condensation. Experimental parameters, such as the pH of the aqueous phase and the influence of titanium alkoxide concentration in the organic phase on the electrochemical signal and material morphology, were investigated. The latter was achieved with fiberglass membranes used as the LLI support during TiO2 interfacial deposition. Cyclic voltammetry was used for the in situ studies, whereas scanning electron microscopy, energy-dispersive X-ray spectroscopy, and infrared spectroscopy were used during ex situ examination. The interfacial polycondensation reaction could be studied using electrified LLI and resulted in the material being a TiO2 film alone or film decorated with particles.  相似文献   
56.
Danon disease is a rare X-linked dominant lysosomal glycogen storage disease that can lead to severe ventricular hypertrophy and heart failure. We report a case of Danon disease with cardiac involvement evaluated with cardiovascular magnetic resonance, including late gadolinium enhancement and perfusion studies.  相似文献   
57.
58.
59.
60.
Klein (Arch Gen Psychiatry, 50, 1993, 306-317) has suggested that panic disorder patients have a false suffocation alarm that may be associated with a lowered threshold for carbon dioxide detection. We compared the thresholds and sensitivities of the central and peripheral chemoreflexes between panic disorder patients and age- and sex-matched healthy volunteers to test this aspect of the hypothesis. We used a modified version of Read's rebreathing technique in 11 panic disorder patients and 10 healthy volunteers to examine the peripheral and central chemoreflex characteristics in these two populations. Subjects were examined during three rebreathing tests: training, hyperoxic (central chemoreflex alone) and hypoxic (combined central and peripheral chemoreflex). Panic symptoms were retrospectively assessed between groups using a DSM-IV derived Panic Symptom Scale. Comparisons of panic disorder patients with agoraphobia and healthy volunteers showed no significant differences in sensitivities or thresholds. Klein's hypothesis is not supported by these data. If a false suffocation alarm exists, its triggering may not be implemented within the respiratory chemoreflexes.  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