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   2071篇
  免费   105篇
  国内免费   14篇
耳鼻咽喉   42篇
儿科学   89篇
妇产科学   69篇
基础医学   132篇
口腔科学   143篇
临床医学   142篇
内科学   583篇
皮肤病学   39篇
神经病学   107篇
特种医学   85篇
外科学   504篇
综合类   21篇
预防医学   30篇
眼科学   71篇
药学   64篇
中国医学   3篇
肿瘤学   66篇
  2024年   3篇
  2023年   14篇
  2022年   37篇
  2021年   54篇
  2020年   29篇
  2019年   33篇
  2018年   40篇
  2017年   44篇
  2016年   66篇
  2015年   74篇
  2014年   99篇
  2013年   104篇
  2012年   189篇
  2011年   159篇
  2010年   84篇
  2009年   87篇
  2008年   174篇
  2007年   198篇
  2006年   142篇
  2005年   129篇
  2004年   106篇
  2003年   74篇
  2002年   67篇
  2001年   38篇
  2000年   23篇
  1999年   27篇
  1998年   5篇
  1997年   4篇
  1996年   10篇
  1995年   3篇
  1994年   4篇
  1993年   2篇
  1992年   8篇
  1991年   6篇
  1990年   5篇
  1989年   7篇
  1988年   3篇
  1987年   10篇
  1986年   6篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   1篇
  1981年   5篇
  1980年   5篇
  1979年   2篇
  1977年   1篇
  1975年   1篇
排序方式: 共有2190条查询结果,搜索用时 0 毫秒
1.
We describe a case of neonatal osteofibrous dysplasia that was diagnosed 3 days after birth. Osteofibrous dysplasia is a fibro-osseous lesion rarely seen in long bones. It is also known as congenital osteitis fibrosa or ossifying fibroma of bones. Although it occurs in children under 10 years of age, it is extremely rare in newborn babies. It must be differentiated from adamantinoma due to their radiological appearance, predilection for tibia and fibula, clinical picture, and certain histological similarities.  相似文献   
2.
Short term cyclosporin A treatment of Beh?et's disease.   总被引:1,自引:1,他引:0       下载免费PDF全文
Eleven separate three-month courses of cyclosporin A, an oral solution 10 mg/kg/day, were administered to eight patients with Behçet''s disease with sight-threatening posterior uveitis. It was found to be effective in arresting the inflammatory activity in the eye as well as the mucocutaneous lesions of Behçet''s disease. Improvement in visual acuity was observed within one week of starting therapy. Severe exacerbations in the ocular and mucocutaneous lesions occurred on withdrawal of the drug. At this dosage side effects included hirsutism in all women, and a slight rise of serum bilirubins in two patients and of blood urea in one patient. The latter two conditions responded rapidly to dose adjustment.  相似文献   
3.
4.
5.
Estrogens have long been known to be important for skeletal homeostasis, but their precise mechanisms of action in bone are still unclear. Mice with targeted deletions of the estrogen receptors alpha (ERalpha) and beta (ERbeta) have been generated by two research groups and several studies performed characterizing the phenotype of ERalpha knockout (ERKOalpha), ERbeta knockout (ERKObeta), or double deletion of ERalpha and ERbeta (DERKO) mice. Initial studies reported a reduction in bone mineral density in male ERKOalpha mice. More extensive analyses have been puzzling, likely because of compensatory mechanisms in ERKO mice. Furthermore, the existence of a third ER continues to be a potential explanation for some actions of estrogen in bone. Other rodent models, including the testicular feminized mouse and rat, the aromatase knockout mouse, and a rat with a dominant negative ER mutation, have added information regarding estrogen's actions in bone. This review summarizes many reports characterizing available rodent models with genetic alterations relevant to estrogen action. The sum of these reports suggests that the ERbeta is not highly protective in bone because loss of its function results in minimal alterations in the skeleton. Furthermore, loss of both the ERalpha and the ERbeta does not account for loss of estrogen action in bone, because the impact of DERKO is seemingly not as great as the impact of gonadectomy on the skeleton. Finally, through studies of ERKO mice and other rodent models of altered sex steroid action, it appears that estrogen may be more protective in the skeleton than androgens.  相似文献   
6.
BACKGROUND: This is a first attempt to evaluate the reliability and factor structure replicability of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) in its Turkish Version. The questionnaire is a self-report 110-item measure that postulates five affective temperaments-the depressive, cyclothymic, irritable, hyperthymic, and anxious-which embody both strengths and liabilities along affective lines. METHODS: The questionnaire was administered to 658 clinically-well subjects in a Turkish university circle. We undertook item analysis and test-retest reliability. We then examined internal consistency through factor analysis with PCA rotation. RESULTS: We found good to excellent test-retest reliability (0.73-0.91), and internal consistency (0.77-0.85). We deleted 10 items with factor loading <0.20 for their own subscales, resulting in a questionnaire with 99 items. Despite considerable overlap between depressive and cognitive anxiety traits, a distinct "nervous"-anxious factor emerged as well, and the hypothesized (original English) 5-factor structure of the TEMPS-A was supported. Cut-offs for each temperament were based on z-scores higher than +2S.D. Dominant irritable (3.7%), nervous-anxious (3.7%) and depressive (3.1%) temperaments were the most common in this population, whereas dominant cyclothymic (1.7%) and hyperthymic (1.2%) temperaments were relatively uncommon. These temperaments tended to lose their intensity with age. As expected, women scored significantly higher on the nervous-anxious, and men on the hyperthymic temperaments. LIMITATIONS: The sample was composed of younger subjects with higher education than the general population of Turkey. Although the distribution of the scores for each of the temperaments deviated somewhat from normal curves, for heuristic reasons we did attempt to provide prevalence rates based on z-scores. CONCLUSION: In this preliminary version of the TEMPS-A, we have retained 100 (of the original 110) traits loading >0.20. Some deleted items referred to sleep, others appeared socially desirability traits in the Turkish culture endorsed by many subjects. Nonetheless, item analyses within each factor revealed traits indicative of personal assets (specific to each temperament) along with those which might represent vulnerability to affective illness. This is in line with the hypothesized original theoretical framework of the senior authors. Even in this "first pass," in its Turkish version the TEMPS-A is a reliable and valid instrument. Further refinement of the instrument will require the study of a nationally representative sample in Turkey.  相似文献   
7.
Diffuse optical tomography with a priori anatomical information   总被引:1,自引:0,他引:1  
Diffuse optical tomography (DOT) poses a typical ill-posed inverse problem with a limited number of measurements and inherently low spatial resolution. In this paper, we propose a hierarchical Bayesian approach to improve spatial resolution and quantitative accuracy by using a priori information provided by a secondary high resolution anatomical imaging modality, such as magnetic resonance (MR) or x-ray. In such a dual imaging approach, while the correlation between optical and anatomical images may be high, it is not perfect. For example, a tumour may be present in the optical image, but may not be discernable in the anatomical image. The proposed hierarchical Bayesian approach allows incorporation of partial a priori knowledge about the noise and unknown optical image models, thereby capturing the function-anatomy correlation effectively. We present a computationally efficient iterative algorithm to simultaneously estimate the optical image and the unknown a priori model parameters. Extensive numerical simulations demonstrate that the proposed method avoids undesirable bias towards anatomical prior information and leads to significantly improved spatial resolution and quantitative accuracy.  相似文献   
8.
9.
10.
Summary A patient with end stage renal disease developed ischaemic skin necrosis and digital gangrene. He had diffuse arterial calcification associated with hyperparathyroidism secondary to renal failure. The patient received inappropriate cyclophosphamide therapy as he had been misdiagnosed as having an inflammatory vasculitis. This clinical picture, previously named calciphylaxis should come into the differential diagnosis of systemic vasculitis in a uraemic patient with hyperparathyroidism.  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