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   38709篇
  免费   3423篇
  国内免费   62篇
耳鼻咽喉   305篇
儿科学   1099篇
妇产科学   966篇
基础医学   5409篇
口腔科学   535篇
临床医学   4452篇
内科学   7145篇
皮肤病学   508篇
神经病学   3765篇
特种医学   1039篇
外科学   4715篇
综合类   916篇
一般理论   136篇
预防医学   5109篇
眼科学   736篇
药学   2502篇
中国医学   25篇
肿瘤学   2832篇
  2023年   393篇
  2022年   611篇
  2021年   1298篇
  2020年   803篇
  2019年   1247篇
  2018年   1283篇
  2017年   946篇
  2016年   973篇
  2015年   1092篇
  2014年   1413篇
  2013年   1935篇
  2012年   2839篇
  2011年   2845篇
  2010年   1493篇
  2009年   1231篇
  2008年   2208篇
  2007年   2107篇
  2006年   1984篇
  2005年   1890篇
  2004年   1717篇
  2003年   1465篇
  2002年   1346篇
  2001年   608篇
  2000年   601篇
  1999年   595篇
  1998年   368篇
  1997年   277篇
  1996年   241篇
  1995年   235篇
  1994年   201篇
  1993年   191篇
  1992年   387篇
  1991年   391篇
  1990年   372篇
  1989年   390篇
  1988年   310篇
  1987年   327篇
  1986年   316篇
  1985年   372篇
  1984年   288篇
  1983年   234篇
  1982年   146篇
  1981年   128篇
  1980年   128篇
  1979年   201篇
  1978年   147篇
  1975年   124篇
  1974年   134篇
  1973年   123篇
  1972年   136篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.

Background  

Statin-related skeletal muscle disorders range from benign myalgias – such as non-specific muscle aches or joint pains without elevated serum creatinine kinase (CK) concentration – to true myositis with >10-fold elevation of serum CK, to rhabdomyolysis and myoglobinuria. The genetic basis of statin-related muscle disorders is largely unknown. Because mutations in the COQ2 gene are associated with severe inherited myopathy, we hypothesized that common, mild genetic variation in COQ2 would be associated with inter-individual variation in statin intolerance. We studied 133 subjects who developed myopathy on statin monotherapy and 158 matched controls who tolerated statins without incident or complaint.  相似文献   
112.
Carotid stenosis in lacunar stroke.   总被引:4,自引:0,他引:4  
The prevalence of extracranial carotid stenosis in patients with a clinical syndrome of lacunar stroke has not been extensively studied using noninvasive methods. We performed carotid duplex sonography on 168 patients referred to the neurosonology laboratory with a diagnosis of ischemic stroke. Strokes were independently classified as lacunar or nonlacunar hemispheric infarction without knowledge of the ultrasound results. We excluded patients with infarcts that were clearly vertebrobasilar, presumed to be cardioembolic, or had occurred greater than 1 year earlier, and patients for whom classification of the nature and location of the event was not possible. Fifty-five patients had lacunar and 54 had nonlacunar stroke. No differences in age, sex, distribution, or prevalence of hypertension, diabetes, prior ischemia, or Hispanic surname existed between the two groups. Tobacco use was more frequent in the nonlacunar group (p less than 0.01). The prevalence of important extracranial carotid stenosis (greater than or equal to 50% diameter reduction) in the lacunar stroke group was 13% (seven of 55) in the ipsilateral and 4% (two of 55) in the contralateral carotid artery. Of the 54 patients with nonlacunar hemispheric stroke, 41% (22) had ipsilateral (p less than 0.01) and 26% (14) had contralateral (p less than 0.01) carotid stenosis. This study suggests that important carotid stenosis is infrequent among patients presenting with a clinical syndrome of lacunar stroke. These data impact on decisions regarding cerebrovascular work-up in such patients.  相似文献   
113.
Sir, The expansion of haemodialysis includes older patients withcomorbidities, poor quality vessels, unsuitable for transplantationor peritoneal dialysis. Vascular access complications accountfor 20% of hospital admissions [1]. With exhausted sites inupper extremities, unusual sites for arteriovenous grafts formationare used [2]. The  相似文献   
114.
115.
A case of glomerulonephritis complicating staphylococcal endocarditis is presented. Hypocomplementaemia and a C3-activating factor in the serum suggested that the patient might have mesangiocapillary glomerulonephritis in association with C3-nephritic factor. Renal biopsy showed that this was not so and further examination of the serum factor showed that it differed from classical C3-nephritic factor because it was not an immunoglobulin. It is postulated that complement activation and glomerulonephritis in staphylococcal endocarditis may be the direct result of a bacterial product. A substance in the serum which activates C3 should be confirmed to be an immunoglobulin before the presence of classical C3-nephritic factor is assumed.  相似文献   
116.
117.
118.
Summary— Acidosis affects multiple steps in the excitation-contraction coupling pathway of myocardium, producing decreased calcium sensitivity of myofibrils and modification of the function of the sarcoplasmic reticulum. Our aim was to evaluate the effectiveness of three different classes of inotropic agents under acidotic conditions: 1) forskolin, an adenylate cyclase activator that enhances cellular cyclic AMP concentrations, 2) elevated extracellular Ca2+ and 3) endothelin-1, an activator of the inositol triphosphate, diacylglycerol pathway. Ferret papillary muscles were mounted in organ baths containing normal physiological solution (pH = 7.4). After baseline tension was measured, the muscles were bathed in an acidotic solution (pH = 6.98) that decreased tension to 40% of the control; subsequently, the muscles were washed with normal physiological solution until they returned to baseline. Each inotropic agent was added to the bathing solution in a concentration sufficient to increase tension by 40% above the baseline. Then the solution was made acidotic (pH = 6.98) in the continuous presence of that concentration of inotropic agent and the resultant steady-state developed tension measured. The increases in tension induced by each inotropic agent at normal pH were adjusted to be similar; in contrast, the response to each drug in acidosis was significantly different. Under acidotic conditions, endothelin-1 was the most effective inotropic agent in restoring the depressed developed tension. This was possibly due to enhancement of the myofilament sensitivity to Ca2+, which was more effective than increasing [Ca2+]i through elevating extracellular Ca2+ or the addition of forskolin which increased [Ca2+]i but desensitized the myofilaments to Ca2+.  相似文献   
119.
Shared care: a review of the literature   总被引:7,自引:1,他引:6  
This review examines broad issues of concern regarding the primary/secondarycare interface. The main purpose was to identify areas of goodpractice which could be adapted for more general use. One ofthe most fundamental aspects identified was communication, whichis discussed in some detail. Also covered are shared prescribingand disease management. The data suggest that the most effectivesystem(s) of shared care has yet to be established. Furtherqualitative and economic evaluations are required, taking intoaccount patient preferences. Although the literature does describecertain practice exemplars, it is clear that inter- and intra-professionalcommunication continues to be a problem. Whilst informationtechnology may provide some of the solutions, it is concludedthat a culture change, which compels health professionals tomake sharing of patient information a much higher priority,is reauired. Keywords. Shared care, seamless care, hospital, general practice, family practice.  相似文献   
120.
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