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   1130篇
  免费   253篇
  国内免费   4篇
耳鼻咽喉   13篇
儿科学   45篇
妇产科学   61篇
基础医学   85篇
口腔科学   35篇
临床医学   171篇
内科学   228篇
皮肤病学   53篇
神经病学   127篇
特种医学   21篇
外科学   167篇
综合类   2篇
预防医学   122篇
眼科学   125篇
药学   40篇
肿瘤学   92篇
  2024年   7篇
  2023年   78篇
  2022年   10篇
  2021年   33篇
  2020年   34篇
  2019年   30篇
  2018年   72篇
  2017年   66篇
  2016年   69篇
  2015年   72篇
  2014年   86篇
  2013年   90篇
  2012年   74篇
  2011年   64篇
  2010年   80篇
  2009年   72篇
  2008年   64篇
  2007年   65篇
  2006年   67篇
  2005年   46篇
  2004年   41篇
  2003年   33篇
  2002年   17篇
  2001年   11篇
  2000年   2篇
  1999年   7篇
  1998年   17篇
  1997年   18篇
  1996年   7篇
  1995年   5篇
  1994年   6篇
  1993年   4篇
  1992年   4篇
  1991年   5篇
  1990年   3篇
  1989年   2篇
  1988年   5篇
  1987年   3篇
  1982年   2篇
  1976年   2篇
  1974年   1篇
  1973年   1篇
  1967年   1篇
  1966年   1篇
  1963年   1篇
  1960年   2篇
  1944年   1篇
  1943年   2篇
  1938年   2篇
  1935年   1篇
排序方式: 共有1387条查询结果,搜索用时 31 毫秒
91.
92.
BackgroundLittle is known about the practice, perceptions and experience of using traditional and complementary medicine (T/CM) for erection difficulties among Asian men.MethodsA total of 10,934 Asian men living in China (n = 2,055), Japan (n = 877), Korea (n = 2,000), Malaysia (n = 3,000) or Taiwan (n = 2,002) were recruited via random digit dialing, street interception and face-to-face interview in the Asian Men's Attitudes To Life Events and Sexuality (MALES) Phase I study. The Phase II study was comprised of a total of 1,286 men who experienced erection difficulties and who lived in China (n = 255), Japan (n = 228), Korea (n = 225), Malaysia (n = 380) or Taiwan (n = 228).ResultsUse of T/CM for erection difficulties (9.1%) was relatively low compared to conventional medicine (83.5%). Among those that seek help and treatment from T/CM, the majority were respondents from Malaysia, followed by respondents from China, whereas respondents from Japan and Korea ranked lowest. Use of a combination of alternative and conventional therapy was prevalent. Erection difficulty was amongst the highest in terms of preference of treatment seeking using traditional approaches after back pain, arthritis and gout. Overall outcome was expressed as ‘Partly satisfied’ with T/CM treatment for erection difficulties. The main reason that T/CM outweighs conventional medicine was because it was perceived that T/CM had fewer side effects than conventional medicine (56.1%). Users of T/CM were mostly middle-aged, married, employed, and perceived their health status and the severity of their erection dysfunction as moderate.ConclusionsThe findings help to identify the differences in practices and beliefs about T/CM among Asian countries and provide useful information to conventional practitioners about the alternative help- and treatment-seeking behaviors for erectile difficulties.  相似文献   
93.
94.
Red cells transfused into a case of haemolysing blackwater fever are destroyed just as readily as the patient's own cells, making it appear that it is not the red cells that are at fault in this condition, but that there is some circulating haemolysin.By an improved spectrophotometric technique it has now been shown that, like those of haemolytic jaundice, the red cells from blackwater fever have an increased fragility to lyso-lecithin, although their fragility to saline is normal, unlike that of the cells of haemolytic jaundice.These two facts taken together make it seem that in blackwater fever the cells may possess some abnormal feature, but that this is probably secondary to more fundamental changes that take place in the cells' environment. By using van Boros' formula it is possible to demonstrate that spherocytosis occurs in blackwater fever and is accompanied by decreases in diameter-thickness ratio, volumes and areas; that these changes in blackwater fever are intermediate between those taking place in haemolytic jaundice and normal controls, and are not related in blackwater fever to changes in hypotonic saline fragility. It is probable that the initial stage in the destruction of the cells is a change in the permeability of the cell membrane, which allows haemoglobin to escape. The cells have later been seen to swell, become “transparent,” and then to disappear. That they have not been broken up can be shown by resuspending them in saline when the “ghosts” reappear. This phenomenon takes place in both lyso-lecithin and snake venom haemolysis. If the process is allowed to continue the cells are finally disrupted, and will not reappear on saline resuspension.In haemolytic jaundice it seems that there may be some defect in the red cell as well as some “splenic factor,” shown by the fact that splenectomy fails to alter the abnormal fragility of the cells to saline, but does stop the periodic haemolysis. A combination of both abnormal cells and splenic factors would seem to be necessary for the destruction of the red cells in this condition. The same cannot be determined for blackwater fever.The enlargement of the spleen in so many of these haemolytic conditions is regarded by many as of considerable significance. The production of lyso-lecithin as a result of the separation of the cells and plasma in this organ has led to the suggestion that this powerfully haemolytic substance may play a part in the haemolyses of certain of these conditions.It is possible that lyso-lecithin fragility is in some way related to the action of this substance on the lipoids or lipo-protein complex in the red cell membrane. It has been shown that the amount of lipoid present in the cell envelope is closely related to the dimensions of the cell, and that the ability of the cell to increase its volume without being disrupted is related to the lipo-protein ratio in its membrane.The kinetics of lyso-lecithin haemolysis have not been worked out, but there is some ground for regarding the process as one of enzyme action where the enzyme lecithinase acting on a substrate of red cells or plasma lecithin results in the production of lyso-lecithin or some allied phosphatide. Lecithinase has been shown to be present in many conditions where haemolytic reactions take place, such as in favism, snake poisoning, Cl. welchii filtrates as well as in the spleen and peripheral blood. The degradation products of the action of lecithinase on lecithin are not always the same, nor are the various lecithinases alike.Although the end product of the action of snake venom lecithinase on lecithin is lyso-lecithin, yet this substance when injected into baboons in relatively huge amounts produces no haemolysis, and only a slight shift of the Price-Jones curve to the right. This is in sharp contrast to the haemolysis that follows the injection of snake venom freed of its neurotoxic factor. It is suggested that this difference may be due to the fact that in the former case the lecithin in the cells and/or plasma is not disturbed, whilst in the case of snake venom injection of the lecithinase present in the venom will split the lecithin of the cells and/or plasma and so disturb the intracellular lipo-protein complex.The part played by the reticulo-endothelial system in the haemolytic process is briefly discussed—the resulting decision being that no precise data are available to enable any conclusions to be reached either upon the part that this system plays in actually destroying red cells, or elaborating haemolysins that later lyse the cells.Proteolytic enzymes may be produced in the macrophages of the reticulo-endothelial system and these have been shown to be capable of destroying red and white cells.  相似文献   
95.
96.
AIM: This paper is a report of part of a study to investigate the burden experienced by families giving care to a relative with dementia, the consequences of care for the mental health of the primary caregiver and the strategies families use to cope with the care giving stressors. BACKGROUND: The cost of caring for people with dementia is enormous, both monetary and psychological. Partners, relatives and friends who take care of patients experience emotional, physical and financial stress, and care giving demands are central to decisions on patient institutionalization. METHOD: A volunteer sample of 172 caregiver/care recipient dyads participated in the study in Cyprus in 2004-2005. All patients were suffering from probable Alzheimer's type dementia and were recruited from neurology clinics. Data were collected using the Memory and Behaviour Problem Checklist, Burden Interview, Center for Epidemiological Studies-Depression scale and Ways of Coping Questionnaire. FINDINGS: The results showed that 68.02% of caregivers were highly burdened and 65% exhibited depressive symptoms. Burden was related to patient psychopathology and caregiver sex, income and level of education. There was no statistically significant difference in level of burden or depression when patients lived in the community or in institutions. High scores in the burden scale were associated with use of emotional-focused coping strategies, while less burdened relatives used more problem-solving approaches to care-giving demands. CONCLUSION: Caregivers, especially women, need individualized, specific training in how to understand and manage the behaviour of relatives with dementia and how to cope with their own feelings.  相似文献   
97.
Ischemic colitis     
  相似文献   
98.
99.
The present study examined the relationship between multiple blood pressure (BP) indices and white matter hyperintensities (WMH) in a sample of 39 older adults with cardiovascular disease (CVD). Resting BP was measured using an automated monitor every 10 min for 2 h. WMH were quantified on FLAIR images and separate indices were generated for neocortical, periventricular and subcortical brain regions. Correlation analyses revealed systolic BP variability was related to neocortical and total WMH. A function of systolic BP variability and average diastolic pressure showed the strongest relationships, including significant correlation to neocortical, subcortical and total WMH. No BP index was related to WMH in periventricular regions. Exploratory analyses showed only the function of systolic BP variability and average diastolic pressure predicted total WMH, whereas as age, CVD conditions and psychosocial factors did not. These findings demonstrate BP variability is an important contributor to WMH in older adults with CVD and suggests it may have differential relationships to WMH in different brain regions. Additional studies are needed to examine the role of autoregulatory systems in the development of WMH, particularly those using beat-to-beat measures of BP.  相似文献   
100.
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