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   722篇
  免费   48篇
耳鼻咽喉   11篇
儿科学   19篇
妇产科学   14篇
基础医学   84篇
口腔科学   60篇
临床医学   55篇
内科学   131篇
皮肤病学   10篇
神经病学   35篇
特种医学   18篇
外科学   128篇
综合类   18篇
预防医学   79篇
眼科学   30篇
药学   33篇
中国医学   13篇
肿瘤学   32篇
  2023年   6篇
  2022年   17篇
  2021年   21篇
  2020年   9篇
  2019年   18篇
  2018年   24篇
  2017年   14篇
  2016年   17篇
  2015年   26篇
  2014年   32篇
  2013年   35篇
  2012年   51篇
  2011年   42篇
  2010年   27篇
  2009年   23篇
  2008年   41篇
  2007年   34篇
  2006年   35篇
  2005年   34篇
  2004年   18篇
  2003年   21篇
  2002年   17篇
  2001年   18篇
  2000年   20篇
  1999年   21篇
  1998年   7篇
  1997年   6篇
  1995年   4篇
  1993年   5篇
  1992年   5篇
  1991年   7篇
  1990年   5篇
  1989年   7篇
  1988年   13篇
  1987年   14篇
  1986年   13篇
  1985年   5篇
  1984年   8篇
  1983年   7篇
  1982年   3篇
  1981年   4篇
  1980年   2篇
  1979年   4篇
  1978年   3篇
  1976年   2篇
  1975年   3篇
  1974年   5篇
  1973年   3篇
  1970年   2篇
  1968年   3篇
排序方式: 共有770条查询结果,搜索用时 15 毫秒
71.
72.
A retrospective clinical and radiologic study was made of 16 children with foot deformities and associated occult spinal abnormalities in a 3-year period. Eleven children had bilateral foot deformities; the deformities were unilateral in five. Midline cutaneous lesions of the back were noted in 13 children; the most common dermal sign was a hairy patch. All children had radiologic features of spinal dysraphism on combined computed tomography (CT) scan and myelogram. Spinal dysraphism was not considered in the initial assessment of four children. Children with foot deformity should therefore have a careful assessment of the spine, including a neurologic evaluation.  相似文献   
73.
Twenty-seven children with vascular deficit associated with the displaced posterolateral type of supracondylar fracture were explored surgically. Twenty-two children had median nerve signs. Associated clinical findings were bruising, tethering or puckering of the skin in the antecubital region, and a palpable subcutaneous medial spike of the proximal humeral fragment, indicating that the brachialis muscle was penetrated. Manipulation was avoided in such cases. At exploration, the neurovascular bundle was found trapped anterior to the fracture edge in 18 cases, dislocated behind the fracture edge in five cases, and separated by the spike in four cases. Fasciotomy of the antecubital region was performed, and the neurovascular bundle was released from entrapment. The vessel pulsated after release in 21 cases, vascular procedures were done in four, and the vessel ends were ligated in two completely lacerated vessels. Manipulation should be avoided in displaced posterolateral supracondylar fractures with neurovascular deficit when there is clinical evidence that the brachialis muscle belly has been buttonholed.  相似文献   
74.
Glomerular injury, occurring either as primary glomerular disease or as part of a systemic disease process, is usually a result of immune-mediated mechanisms. The morphologic reaction pattern has a diverse spectrum of appearance, ranging from normal by light microscopy in minimal change disease to crescentic forms of glomerulonephritis, with conspicuous disruption of the normal glomerular morphology. The mechanisms of glomerular immune deposit formation include trapping of circulating antigen–antibody complexes and the in situ formation of immune complexes within the glomerulus. While the majority of postinfectious immune-complex-mediated glomerulonephritides are believed to result from the deposition of circulating antigen–antibody complexes, preformed outside of the kidney and secondarily deposited in the kidney, the notion of forming in situ antigen–antibody complexes to either planted antigens or to integral structural components of the glomerulus, through “cross-reacting” autoimmune reactions, is gaining popularity in a variety of forms of glomerulonephritides. Patients with HIV infection may develop a spectrum of renal pathology, the glomerular manifestations of which include both antigen–antibody complex and nonimmune-complex-mediated pathogenetic mechanisms. Similarly, patients with Streptococcal infections, Hepatitis B virus, or Hepatitis C virus infection may develop a spectrum of glomerulonephritides, which are predominantly immune-complex-mediated. Therapy for glomerular diseases due to HIV, hepatitis B, or C virus infections remains a challenge.  相似文献   
75.
This paper examines the complex interconnections between the development of health promotion and multidisciplinary public health, respectively. Health promotion takes a distinctive interdisciplinary and multiprofessional perspective on health. Historically, it has brought together practitioners from varied disciplinary backgrounds, education and training. It therefore brings real advantages to the public health enterprise, where the goal is to bridge organisations, professions and partners to collectively address key determinants of health in the most effective manner. This paper debates the contribution health promotion has made to the development of multidisciplinary public health over the past 30 years and explores the principles, values, professional bases and practices of both. It is argued that health promotion's contribution to the development of 'the new public health' was critical, while its status and role within multidisciplinary public health remain problematic and unresolved. The nature of these dilemmas is discussed, reflecting on missed opportunities and possible resolutions.  相似文献   
76.
77.
Skin hyper‐pigmentation is a condition initiated by the overproduction of melanin existing in the melanocytes. Melanin pigment is responsible for the colour of skin in humans. It is formed through a series of oxidative reactions involving the amino acid tyrosine in the presence of the key enzyme tyrosinase. In continuation with our efforts to identify tyrosinase inhibitors from plants sources, the methanol extract from leaf, bark and fruit of Ceratonia siliqua were screened for tyrosinase inhibition and diphenolase activity. The bark extract exhibited significant inhibition on mushroom tyrosinase using L‐tyrosine as a substrate and showed diphenolase activity. The extract further significantly lowered tyrosinase mRNA levels in B16‐F10 mouse melanocytes. Bioassay‐guided fractionation led to the isolation of six compounds. Compounds (?)‐epicatechin‐3‐O‐gallate, 1,2,3,6‐tetra‐O‐galloyl‐ß‐D‐glucose and gallocatechin‐3‐O‐gallate showed tyrosinase inhibitions with the IC50 values of 27.52, 83.30 and 28.30 µg/mL, respectively. These compounds also exhibited L‐DOPA activities with IC50 values of >200, 150 and 200 µg/mL, respectively. A clinical study was conducted using 20 volunteers in a patch testing trial for irritancy potential and skin depigmentation. The clinical results showed the sample to be non‐irritant with irritancy potential of ?34.21 and depigmentation trial showed an improvement in the even skin tone of UV induced pigmentation at 3% after 28 days of application. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
78.
Background: In severe mitral regurgitation, a subset of patients who are asymptomatic may develop left ventricular decompensation before changes in echocardiographic parameters become evident. Since N-terminal brain natriuretic peptide (NT-proBNP) is used to detect early heart failure, we hypothesised that NT-proBNP would be activated in patients with mitral regurgitation. Methods: Patients submitted to surgery were prospectively evaluated over eight months in the Department of Cardiology at Inkosi Albert Luthuli Central Hospital. Control patients with severe mitral regurgitation were obtained from the outpatient clinic. In order to define their value in identifying left ventricular decompensation, NT-proBNP levels and tissue Doppler imaging (TDI) indices were simultaneously measured and compared with conventional echocardiographic indices at baseline and this was repeated at one week and at six weeks after valve replacement. Results: Mean NT-proBNP levels were markedly elevated pre-operatively in all surgical cases compared to controls (p = 0.0001). The diastolic E-mitral/E-annulus ratio, measured using TDI, was higher in the study group, indicating higher left ventricular filling pressure present in the study group. NT-proBNP levels increased further at one week after surgery and subsided at the six-week follow-up visit to levels similar to the control group. The TDI diastolic ratio also decreased at one week, and increased slightly again at the six-week follow up. These changes were accompanied by significant reduction in left atrium and left ventricular chamber dimensions with an increase in the ejection fraction from one to six weeks. Conclusion: Marked differences in mean NT-proBNP levels and TDI ratios between the study and control groups suggest that using TDI and NT-proBNP assays may detect covert left ventricular decompensation.  相似文献   
79.
80.

Objective

To estimate the global cost of establishing and operating the educational and refractive care facilities required to provide care to all individuals who currently have vision impairment resulting from uncorrected refractive error (URE).

Methods

The global cost of correcting URE was estimated using data on the population, the prevalence of URE and the number of existing refractive care practitioners in individual countries, the cost of establishing and operating educational programmes for practitioners and the cost of establishing and operating refractive care facilities. The assumptions made ensured that costs were not underestimated and an upper limit to the costs was derived using the most expensive extreme for each assumption.

Findings

There were an estimated 158 million cases of distance vision impairment and 544 million cases of near vision impairment caused by URE worldwide in 2007. Approximately 47 000 additional full-time functional clinical refractionists and 18 000 ophthalmic dispensers would be required to provide refractive care services for these individuals. The global cost of educating the additional personnel and of establishing, maintaining and operating the refractive care facilities needed was estimated to be around 20 000 million United States dollars (US$) and the upper-limit cost was US$ 28 000 million. The estimated loss in global gross domestic product due to distance vision impairment caused by URE was US$ 202 000 million annually.

Conclusion

The cost of establishing and operating the educational and refractive care facilities required to deal with vision impairment resulting from URE was a small proportion of the global loss in productivity associated with that vision impairment.  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