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   2046篇
  免费   122篇
  国内免费   14篇
耳鼻咽喉   9篇
儿科学   104篇
妇产科学   117篇
基础医学   208篇
口腔科学   51篇
临床医学   206篇
内科学   399篇
皮肤病学   49篇
神经病学   92篇
特种医学   153篇
外科学   218篇
综合类   136篇
预防医学   145篇
眼科学   13篇
药学   133篇
  1篇
中国医学   77篇
肿瘤学   71篇
  2021年   21篇
  2020年   15篇
  2019年   15篇
  2018年   28篇
  2017年   29篇
  2016年   21篇
  2015年   44篇
  2014年   53篇
  2013年   53篇
  2012年   83篇
  2011年   89篇
  2010年   75篇
  2009年   76篇
  2008年   69篇
  2007年   71篇
  2006年   64篇
  2005年   55篇
  2004年   31篇
  2003年   42篇
  2002年   34篇
  2001年   46篇
  2000年   31篇
  1999年   33篇
  1998年   49篇
  1997年   61篇
  1996年   47篇
  1995年   47篇
  1994年   59篇
  1993年   36篇
  1992年   22篇
  1991年   21篇
  1990年   18篇
  1989年   32篇
  1988年   34篇
  1987年   33篇
  1986年   26篇
  1985年   17篇
  1984年   19篇
  1983年   16篇
  1982年   13篇
  1981年   23篇
  1980年   16篇
  1959年   35篇
  1958年   59篇
  1957年   87篇
  1956年   45篇
  1955年   75篇
  1954年   67篇
  1953年   17篇
  1952年   14篇
排序方式: 共有2182条查询结果,搜索用时 11 毫秒
21.
22.
23.
24.
25.
BackgroundThe search for nonsurgical cosmetic procedures has increased considerably in recent years. A new injection technique, using vector direction, has shown good results in improving facial aesthetics but to date has only been performed with hyaluronic acid which can be associated with a risk of vascular complications. Therefore, in clinical practice, it would be interesting to assess this technique with a liquid product already widely used in the facial region, and at the same time bring the same aesthetic benefits, but with greater durability than hyaluronic acid.ObjectiveTo investigate the improvement of facial morphology in patients with facial flaccidity submitted to the vector technique using poly-L-lactic acid (PLLA) (Sculptra®; Galderma, Lausanne, Switzerland).Case SeriesHere we report the outcomes of three cases of female patients, aged between 41 and 55 years, seeking improvement of facial flaccidity. In each patient, PLLA was applied in the posterior temporal region as a bolus, in three points, with a 2-mL injection in the upper region, 1.5mL in the midpoint, and 1.5mL at the bottom point. Each of the three patients showed an improvement in face morphology, with concomitant improvement in the support and stretching of the face and improvement in skin sagging in the upper, middle, and bottom regions.ConclusionThe vector technique with PLLA is a viable alternative for the treatment of patients with facial skin flaccidity, providing harmonious and progressive improvement in the face morphology.  相似文献   
26.
This report describes a rare case of coexistence of benign phyllodes tumor, which measured 9 cm in the right breast, and invasive ductal carcinoma of 6 cm in the left breast, synchronous and independent, in a 66-year-old patient. The patient underwent a bilateral mastectomy due to the size of both lesions. Such situations are rare and usually refer to the occurrence of ductal or lobular carcinoma in situ when associated with malignant phyllodes tumors, and more often in ipsilateral breast or intra-lesional.  相似文献   
27.
28.
29.
In congestive heart failure (CHF), the neurohormonal mechanisms that cause renal vasoconstriction, particularly those depending on the renin-angiotensin system, could interfere with renal vasodilating mechanisms. To elucidate this issue, we studied the kidney response to an amino acid infusion (known to cause renal vasodilation in healthy individuals) in eight patients with CHF. We found that the amino acid infusion (0.7 mL/kg/h of a 10% solution) elicited no renal hemodynamic response, in marked contrast to healthy subjects. We next hypothesized that the renin-angiotensin system (known to be activated in heart failure) has a role in the lack of response to the amino acid infusion. To test this hypothesis, we repeated the study after two 5-mg doses of enalapril, an inhibitor of the angiotensin-converting enzyme, administered 12 hours apart. After enalapril treatment, the amino acid infusion caused a 45% increase in mean renal blood flow (RBF) from 383 +/- 55 to 557 +/- 51 mL/min at the fifth hour (P < 0.05). This normalization of the renal response to the amino acid infusion occurred without changes in cardiac output or in systemic vascular resistance. Hence, the renal fraction of the cardiac output increased during the amino acid infusion. The recovery of the renal vascular response was not accompanied by an increase in glomerular filtration rate (GFR; filtration fraction decreased), suggesting a predominant efferent arteriole dilatation. Our study shows that, in heart failure, the kidney loses its ability to increase RBF in response to an amino acid load. This lack of renal vascular response can be restored by inhibiting the renin-angiotensin system and is unrelated to changes in systemic hemodynamics.  相似文献   
30.
The purpose of this study was to assess the impact of a corticosteroid-free maintenance immunosuppression on graft survival in kidney transplantation. We analyzed 79 patients who were transplanted between June 1, 2006 and May 31, 2007. We excluded hyperimmunized patients, second transplantations, living donors, and black recipients. Patients underwent induction with thymoglobulin or basiliximab, followed by treatment with mycophenolate mofetil (MMF), tacrolimus, and methylprednisolone. On the 5th day, the patients were divided into 2 groups: group A (n = 45) discontinued steroid therapy; group B (n = 34) continued prednisone therapy. We performed a comparative analysis of incidence of delayed graft function (DGF), acute rejection episodes (ARE), renal function at 6 and 12 months, graft and patient survivals, causes of graft loss, and mortality. The 2 groups were similar for donor, recipient, and graft characteristics. The incidences of DGF were 8.9% in group A and 14.7% in group B; those for ARE were 2.3% in group A and 13.8% in group B (P = .077). The mean serum creatinine levels at 6 and 12 months were similar. There were 8 graft losses: 3 in group A (3 deaths with functioning grafts) and 5 in group B (1 death, 3 vascular causes, 1 kidney nonfunction). The 4 deaths were due to infection (n = 3) or neoplasia (n = 1). Graft survivals at 1 year were 98% in group A and 85% in group B, and patient survivals were 98% and 97%, respectively. An immunosuppressive regimen using antibody induction and steroid-free treatment proved to be effective in low-risk patients.  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