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   705篇
  免费   27篇
  国内免费   6篇
耳鼻咽喉   4篇
儿科学   20篇
妇产科学   11篇
基础医学   59篇
口腔科学   1篇
临床医学   53篇
内科学   129篇
皮肤病学   10篇
神经病学   72篇
特种医学   12篇
外科学   224篇
综合类   3篇
预防医学   28篇
眼科学   29篇
药学   38篇
中国医学   2篇
肿瘤学   43篇
  2024年   1篇
  2023年   8篇
  2022年   18篇
  2021年   23篇
  2020年   4篇
  2019年   17篇
  2018年   16篇
  2017年   10篇
  2016年   15篇
  2015年   25篇
  2014年   32篇
  2013年   33篇
  2012年   45篇
  2011年   66篇
  2010年   35篇
  2009年   24篇
  2008年   42篇
  2007年   59篇
  2006年   44篇
  2005年   28篇
  2004年   39篇
  2003年   43篇
  2002年   38篇
  2001年   9篇
  2000年   9篇
  1999年   7篇
  1998年   10篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1994年   2篇
  1993年   2篇
  1992年   5篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
排序方式: 共有738条查询结果,搜索用时 15 毫秒
1.
Hyperexcitability of the motor system has been reported in Parkinson's disease (PD). We evaluate how cutaneous afferents modulate motor excitability in PD patients and whether abnormal modulation is correlated to parkinsonian symptoms. Digital stimulation causes abnormal enhancement of motor responses in patients. This effect may be one of the features of motor hyperexcitability in PD. Cutaneomotor hyperexcitability correlates with clinical scores, suggesting that abnormal processing of cutaneous inputs might contribute to the pathogenesis of parkinsonian symptoms.  相似文献   
2.
OBJECTIVE: An animal model has been designed to assess the feasibility of off-pump mitral valve replacement using valved stents. METHODS: Glutaraldehyde-preserved homograft was sutured inside a prosthetic tube (Dacron). Then, two self-expandable nitinol Z-stents were sutured on the external surface of the prosthesis in such a way to create two self-expanding crowns for fixation. In adult pigs and under general anesthesia, the left atrium was exposed through a left thoracotomy and atrio-ventricular roadmapping was performed with intravascular ultrasound (IVUS) and fluoroscopy. The double-crowned valved stents were loaded into a delivery sheath. The sheath was then introduced into the left atrium and the valved stents was deployed in mitral position in such a way that the part in between the two stents was at the level of the mitral annulus. Intracardiac Unltrasound (ICUS) was used to assess the valve function. Hemodynamic parameters were gathered as well. Animal survived for no more than 3h after the valve deployment and gross anatomy examination of the left heart was carried out. RESULTS: The mean height of the valved stents was 29.4+/-0.2 mm, with an internal diameter of 20.4+/-1.0mm, and an external diameter of 25.5+/-0.8 mm. The procedure was successfully carried out in eight animals. In vivo evaluation showed a native mitral annulus diameter of 24.9+/-0.6 mm, and a mean mitral valve area of 421.4+/-17.5 mm2. ICUS showed a mild mitral regurgitation in three out of eight animals. Mean pressure gradient across the valved stents was 2.6+/-3.1 mmHg. Mean pressure gradient across the left ventricular outflow tract (LVOT) was 6.6+/-5.2 mmHg. The mean survival time was 97.5+/-56.3 min (survival time range was 40-180 min). One animal died due to the occlusion of the LVOT because of valved stents displacement. Postmortem evaluation confirmed correct positioning of the valved stent in the mitral position in seven out of eight animals. No atrial or ventricular lesions due to the valved stents were found. CONCLUSIONS: Off-pump implantation of a self-expandable valved stent in the mitral position is technically feasible. Further studies will assess if this procedure is also feasible in humans.  相似文献   
3.
Molecular cytogenetic characterization of proximal-type epithelioid sarcoma   总被引:2,自引:0,他引:2  
Proximal-type epithelioid sarcoma is a recently described soft-tissue tumor that is distinguished from conventional-type epithelioid sarcoma by a far more aggressive clinical course, frequent location in the proximal anatomic regions, and variable rhabdoid morphology. Because of their rarity and peculiar morphology, proximal-type epithelioid sarcomas frequently pose serious diagnostic dilemmas, being easily misdiagnosed as a variety of other malignant neoplasms. To date, the information available on the genetic alterations associated with this tumor entity has been confined to single conventional cytogenetic reports. In this article, we present the results of a conventional and molecular cytogenetic analysis of six proximal-type epithelioid sarcomas. Spectral karyotyping analysis of these cases deciphered the characteristics of several marker chromosomes and complex translocations, leading to the recognition of recurrent rearrangements. The most frequently involved chromosome arm was 22q, and the identification of two cases with a similar translocation, t(10;22), suggests a role for one or more genes on chromosome 22 in the pathogenesis of this tumor and provides an opportunity for finely mapping the translocation-associated breakpoints. Chromosome arm 8q gain was also a frequent event and correlated with gain of MYC gene copy number, as demonstrated by fluorescence in situ hybridization. A review of both cases reported in the literature and those presented in this study reinforced the involvement of chromosomes 8 and 22 and also indicated frequent rearrangements of chromosomes 7, 14, 18, and 20.  相似文献   
4.
In recent years, major and widely accepted information security understandings and achievements confirm that the problem is complex. They clarify that technologies are fundamental tools, but management processes have even bigger relevance, as also prestigious international magazines dossier clearly explained recently. Such a magazine attention outlines the wide impact that the subject has on watchful decision makers. ISO17799 is an emerging standard in information security. In principle there are no reasons for considering it not applicable to the health care sector. In practice, because of both the just conceptual level of the standard and the peculiarities of the health care data and institutions, a lot of analysis and design work need to be invested any time a health care institution decides to deal with the subject. CEN/ENV 12924 is another emerging standard certainly more on the spot of the health care. Nevertheless, it also asks for evident further investigation. The practical case of information security design, implementation, management, and auditing inside a multi-specialty provincial Italian hospital will be described.  相似文献   
5.
Summary We investigated the role of urinary testosterone levels as a marker of risk of recurrent disease in 113 operable breast cancer patients (70 premenopausal, 43 postmenopausal). Twenty-four-hour urine collections for testosterone measurement were obtained before surgical treatment, between 20–40 days thereafter, and then every 6 months for 5 years. The cutoff values to separate high testosterone (A+) from normal testosterone (A–) were 8.0µg/24h in premenopause and 4.9µg/24h in postmenopause. Urinary testosterone levels were considered high when they exceeded the cutoff value in at least 2 of the first 3 measurements (pretreatment, post-treatment, 6 months) of each patient. According to the aforementioned criterion, 33 patients (29.2%) had high testosterone levels, which were associated to axillary node involvement in 16 patients. Thirteen of the latter relapsed during the 5-year follow-up period (5/7 in premenopause, 8/9 in postmenopause). Relapse-free survival (RFS) curves were drawn only for node-positive patients owning to the small number of recurrences observed in the node-negative group. In premenopausal node-positive patients, RFS was significantly different for patients presenting high and normal urinary testosterone levels (77% vs 28%, respectively; logrank test, p< 0.006). In postmenopausal node-positive patients, RFS was also different between the two groups (54% vs 11% in high and normal excretors, respectively) but the difference was not statistically significant. The present findings suggest that urinary testosterone is a prognostic indicator of early breast cancer recurrence in node-positive patients.  相似文献   
6.
BACKGROUND/AIMS: Strictureplasty (SP) or miniresective 'bowel-sparing' techniques (MR) can prevent the risk of intestinal stomia and short bowel syndrome in patients affected by Crohn's disease (CD). The aim of this study was to analyze the perioperative morbidity and mortality in 104 of 138 consecutive patients treated for CD complications using bowel-sparing techniques. We also considered the factors that may be related to the risk of perioperative complications and the long-term outcome. METHODS: One hundred and four patients were treated with SP and/or MR and then included in a prospectively maintained database. The factors claimed to influence perioperative complications were analyzed using Fisher's exact test for categorical observations and the Mann-Whitney U test for continuous variables. A multivariate analysis, using logistic regression, and a long-term time-to-event analysis using the Kaplan-Meier function, were also performed. RESULTS: Perioperative mortality was nil. In relation to the 6 postoperative complications (5.8%), 4 patients underwent minimal bowel resection (MR), 1 a MR with SP, and 1 SP alone. Three of these patients (2.9%) needed reoperation for septic complications, and 3 (2.9%) were treated as outpatients for enterocutaneous fistulas. A correlation (p < 0.05) was found between low serum hemoglobin levels and postoperative complications at univariate and multivariate analyses. The 5-year surgical recurrence-free rate was 75% overall, 73% for patients treated with SP, 78% with MR, and 77% with MR + SP. CONCLUSIONS: Postoperative complications are not related to conservative or miniresective surgery even when active disease is present at the resection margins or the site of SP. The higher risk reported for patients with low serum hemoglobin and hematocrit levels suggests that surgeons should consider using preoperative iron and vitamin support, parenteral nutrition and erythropoietin therapy, when necessary, in those cases. Our postoperative morbidity, mortality and long-term surgical recurrence rate results support the efficacy and safety of SP and MR surgery in the treatment of complicated CD.  相似文献   
7.
BACKGROUND: Giant myomas of the uterus are uncommon, particularly in developed countries. CASE: This report illustrates a case of a woman with a bilobated giant myoma of the uterus weighed in total 27.7 kg. The patient had an abdominal distension first noted 18 months before and the personal history evidenced difficulties in walking and tiredness. Abdominal hysterectomy and bilateral salpingo-oophorectomy were carried out. CONCLUSIONS: The knowledge of the different clinical manifestation of these myomas may allow to face that with adequate perioperative care, in order to assure a carefully and successfully surgery, although sometimes a benign pathology may be not easy to suspect in a first time.  相似文献   
8.
9.
10.
Introduction: Hepatitis C virus (HCV) infection has been associated with a large spectrum of glomerular lesions in both native and transplanted kidneys. The most common HCV-associated renal disease is type I membranoproliferative glomerulonephritis usually, but not invariably, in the context of type II mixed cryoglobulinemia (MC). HCV infection is also the major cause of MC, a systemic vasculitis characterized by involvement of small and, less frequently, medium-sized vessels. Conflicting data exist on the treatment of HCV-associated glomerular disease.

Areas covered: This review examines the drugs used for management of HCV-related kidney disease and discusses current and new strategies. All literature concerning treatment of HCV-associated kidney disease has been retrieved by electronic (Medline) and manual searches.

Expert opinion: Various approaches have been recommended for the treatment of HCV-related glomerular disease, including immunosuppressive therapy (corticosteroids, cytotoxic agents and mAbs) and antiviral therapy. These regimens should be considered according to the level or proteinuria and kidney failure. Immunosuppressive agents are recommended in patients with nephrotic syndrome and/or rapidly progressive kidney failure. Antiviral treatment based on IFN and/or ribavirin or triple antiviral therapy (PEGylated-IFN/ribavirin/telaprevir or boceprevir) has been adopted in patients with moderate proteinuria and slow loss of kidney failure; however, the number of patients enrolled was small. Some patients with HCV-related cryoglobulinemic glomerulonephritis have been treated with rituximab but some issues about its role remain to be clarified. The antiviral treatment of HCV-related glomerular disease is expected to improve in the near future with new agents provided with greater efficacy and safety. However, the affordability of these drugs remains a pivotal issue, particularly in low-income countries.  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