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   995篇
  免费   80篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   56篇
妇产科学   14篇
基础医学   103篇
口腔科学   43篇
临床医学   79篇
内科学   187篇
皮肤病学   11篇
神经病学   119篇
特种医学   105篇
外科学   188篇
综合类   66篇
预防医学   37篇
眼科学   7篇
药学   26篇
中国医学   4篇
肿瘤学   35篇
  2023年   4篇
  2022年   10篇
  2021年   14篇
  2020年   9篇
  2019年   8篇
  2018年   19篇
  2017年   14篇
  2016年   16篇
  2015年   26篇
  2014年   23篇
  2013年   35篇
  2012年   33篇
  2011年   43篇
  2010年   55篇
  2009年   36篇
  2008年   26篇
  2007年   40篇
  2006年   48篇
  2005年   30篇
  2004年   40篇
  2003年   38篇
  2002年   33篇
  2001年   27篇
  2000年   46篇
  1999年   23篇
  1998年   26篇
  1997年   27篇
  1996年   40篇
  1995年   19篇
  1994年   21篇
  1993年   22篇
  1992年   23篇
  1991年   19篇
  1990年   24篇
  1989年   20篇
  1988年   18篇
  1987年   15篇
  1986年   11篇
  1985年   14篇
  1984年   9篇
  1983年   7篇
  1982年   5篇
  1981年   9篇
  1980年   6篇
  1979年   9篇
  1978年   7篇
  1977年   8篇
  1976年   7篇
  1975年   10篇
  1974年   4篇
排序方式: 共有1082条查询结果,搜索用时 0 毫秒
11.
Mechanisms that contribute to increased female susceptibility to multiple sclerosis can be studied in the murine model of experimental autoimmune encephalomyelitis (EAE). In this report, we compared oral tolerance induction in male and female B10.PL mice using fed myelin basic protein (MBP) Ac1-11 peptide or a high-affinity analogue, Ac1-11[4Y]. We found that fed Ac1-11[4Y] peptide, but not native Ac1-11, could limit cellular infiltration into the central nervous system (CNS) and protect male mice from EAE, an effect that was completely obviated by castration. In contrast, female mice could not be orally tolerized or protected from EAE with either peptide. Tolerance induction in males was reflected by the appearance of Ac1-11[4Y]-reactive splenocytes that produced a sharply increased ratio of transforming growth factor (TGF)-beta:interleukin (IL)-2 and induced bystander suppression. These data directly demonstrate gender differences in regulatory T cells, and support the concept that androgens are involved in governing oral tolerance to EAE.  相似文献   
12.
BACKGROUND: Blunt carotid arterial injuries (BCI) have the potential for devastating outcomes. A paucity of literature and the absence of a formal BCI grading scale have been major impediments to the formulation of sound practice guidelines. We reviewed our experience with 109 BCI and developed a grading scale with prognostic and therapeutic implications. METHODS: Patients admitted to a Level I trauma center were evaluated with cerebral arteriography if they exhibited signs or symptoms of BCI or met criteria for screening. Patients with BCI were treated with heparin unless they had contraindications, and follow-up arteriography was performed at 7 to 10 days. Endovascular stents were deployed selectively. A prospective database was used to track the patients. RESULTS: A total of 76 patients were diagnosed with 109 BCI. Two-thirds of mild intimal injuries (grade I) healed, regardless of therapy. Dissections or hematomas with luminal stenosis (grade II) progressed, despite heparin therapy in 70% of cases. Only 8% of pseudoaneurysms (grade III) healed with heparin, but 89% resolved after endovascular stent placement. Occlusions (grade IV) did not recanalize in the early postinjury period. Grade V injuries (transections) were lethal and refractory to intervention. Stroke risk increased with injury grade. Severe head injuries (Glasgow Coma Scale score < or =6) were found in 46% of patients and confounded evaluation of neurologic outcomes. CONCLUSION: This BCI grading scale has prognostic and therapeutic implications. Nonoperative treatment options for grade I BCI should be evaluated in prospective, randomized trials. Accessible grade II, III, IV, and V lesions should be surgically repaired. Inaccessible grade II, III, and IV injuries should be treated with systemic anticoagulation. Endovascular techniques may be the only recourse in high grade V injuries and warrant controlled evaluation in the treatment of grade III BCI.  相似文献   
13.
14.
Zusammenfassung Wir berichten über ein 7 Jahre altes M?dchen, das 14 Tage nach einer Nierentransplantation an Varizellen erkrankte. Erste Symptome waren krampfartige Bauchschmerzen mit radiologischen Hinweisen auf einen Obturationssubileus bei Obstipation. Als nach abführenden Ma?nahmen keine Besserung auftrat, wurde eine Probelaparotomie mit Entfernung des Tenckhoff-Dialysekatheters durchgeführt. Dabei zeigte sich kein pathologischer Befund, insbesondere fanden sich keine Briden. Zwei Tage nach Beginn der abdominalen Symptomatik trat ein zun?chst uncharakteristisches Exanthem auf. Aus den sich in den n?chsten 12 h entwickelnden Bl?schen konnte Varicella-Zoster-Virus isoliert werden. Trotz hochdosierter Gabe von Aciclovir und Varicella-Zoster-Immunglobulin entwickelte sich ein fulminantes Leberversagen mit Verbrauchskoagulopathie. Die Patientin verstarb am 18. postoperativen Tag trotz intensiver supportiver Therapie im Multiorganversagen. Diskussion: Vor dem Hintergrund dieser letalen Varizelleninfektion wird auf die Komplikationen und die teilweise untypischen Verl?ufe von Windpocken bei immunsupprimierten Kindern hingewiesen. Eine aktive Impfung ist daher bei seronegativen Patienten vor einer geplanten Organtransplantation zu fordern.   相似文献   
15.
BACKGROUND: Despite continued improvement in medical therapy, empyema remains a challenging problem for the surgeon. Multiple treatment options are available; however, the optimal therapeutic management has not been elucidated. METHODS: A retrospective review was performed of all adult patients admitted to Denver Health Medical Center between January 1, 1993, and December 31, 1998, with the diagnosis of empyema. Data tabulated included patient demographics, presentation, chest computed tomography (CT) findings, treatment, and outcome. RESULTS: Empyema was diagnosed in 58 patients, 45 cases of which were multiloculated at the time of presentation. Empyema was secondary to pneumonia is 41 patients and posttraumatic in 15. In addition to antibiotic therapy, initial treatment included chest tube drainage alone (n = 6), chest tube drainage with primary operation (n = 19), and chest tube drainage with intrapleural fibrinolytic therapy (n = 33). In 15 patients (45%), fibrinolytic therapy failed. Initial chest CT revealed a pleural peel in 5 patients treated with fibrinolytics and all failed. Multiloculation, however, was not a factor in failure of fibrinolysis. Moreover, chest CT missed the presence of a pleural peel in 17 of 31 patients documented to have a significant peel at the time of thoracotomy. CONCLUSION: Multiple therapeutic options are available for the management of empyema. Multiloculation is not a contraindication to an initial trial of chest tube drainage or fibrinolytic therapy. In contrast, CT evidence of a pleural peel uniformly predicted failure of nonoperative treatment.  相似文献   
16.
The pandemic spread of an infectious disease poses a plethora of challenges to society, clinicians, health care providers and regulating authorities. In order to mount a rapid response and to provide hope in a potentially catastrophic situation as the current COVID-19 pandemic, emergency plans, regulations and funding strategies have to be developed on regional, national and international levels. The speed needed to establish rapid response programs is challenged by the dynamics of the spread of the disease, the concurrent and competing development of different and potentially more effective treatment options, and not the least by regulatory uncertainty. Convalescent plasma, that is plasma collected from patients who have recovered from COVID-19 infections, has emerged as one of the first potential treatment options in the absence of drugs or vaccines with proven efficacy against SARS-CoV-2. The societal aspects of convalescent plasma and the public awareness gave an additional boost to the rapid employment of convalescent plasma donation platforms immediately after the SARS-CoV-2 outbreak. At the same time, uncertainty remains as to the efficacy of convalescent plasma. With evidence mostly limited to empirical reports, convalescent plasma has been used for decades for the prophylaxis and treatment of various infectious diseases. Clinical trials have addressed different infectious agents, stages of disease, target groups of patients and yielded sometimes inconclusive results. The aim of this short review is to delineate the regulatory background for the emergency use of convalescent plasma in the USA, in the European Union and in Germany, and the transition to the setting of clinical trials. In addition, we describe observations made in the process of collecting COVID-19 convalescent plasma (herein referred to as CCP), and formulate proposals to further improve the framework for rapid responses in future emergency situations.  相似文献   
17.
The impact of chronological age on longitudinal body growth from early childhood through adolescence using detailed anthropometric methods has not yet been studied in children with chronic kidney disease (CKD). We have evaluated growth failure by measuring four components of linear growth: body height (HT), sitting height (SHT), arm length (AL) and leg length (LL). Data were prospectively collected for up to 7 years on 190 boys (3–21 years old) with congenital or hereditary CKD (all had developed at least stage 2 CKD by the age of 10 years). Patients showed the most severe growth failure in early childhood, followed by an acceleration in growth in pre-puberty, a slowing-down of growth at puberty, as expected, and thereafter a late speeding-up of growth until early adulthood. This pattern was observed irrespective of the degree of CKD and different treatment modalities, such as conservative treatment, recombinant human growth hormone (rhGH) therapy or transplantation. LL showed the most dynamic growth changes of all the parameters evaluated and emerged as the best indicator of statural growth in children with CKD. A specific age-dependent pattern of physical growth was identified in pediatric male CKD patients. This growth pattern should be considered in the evaluation of individual growth and the assessment of treatment efficacy such as rhGH therapy.  相似文献   
18.
Mutations within the low density lipoprotein (LDL)-receptor gene result in familial hypercholesterolemia, an autosomal dominant inherited disease. Clinical homozygous affected subjects die of premature coronary artery disease as early as in early childhood. We identified a girl at the age of five yr with clinical homozygous familial hypercholesterolemia presenting with achilles tendon xanthomas and arcus lipoides. Her total cholesterol reached up to 1050 mg/dL. Molecular characterization of the LDL-receptor gene revealed a homozygous p.W577R mutation. Despite intensive treatment interventions with the combination of diet, statins, colestipol, and LDL-apheresis, the patient developed symptomatic coronary artery disease at the age of 16 yr. Subsequently, orthotopic liver transplantation was performed to cure the defective LDL-receptor gene. Clinical follow-up for almost nine yr post-transplantation revealed excellent liver function, normal liver enzymes, normal LDL-cholesterol, and regression of both tendon xanthomas and symptomatic coronary artery disease. In conclusion, liver transplantation can effectively reduce LDL-cholesterol in a familial hypercholesterolemia recipient with subsequent regression of xanthomas and atherosclerosis. Timing is extremely important in these exceptional cases to exclude the demand for heart transplantation due to severe coronary artery disease. In addition, the identification of the LDL-receptor as etiology of clinical homozygous hypercholesterolemia is a prerequisite once liver transplantation is considered as therapeutic option.  相似文献   
19.
BACKGROUND: To study the effect of donor age on kidney function, the authors investigated matched pairs from the same kidney donor given to a pediatric or an adult recipient. METHODS: Fifteen matched pairs of an adult and a pediatric patient, selected from the Eurotransplant registry, receiving the renal graft from the same cadaveric donor were selected for analysis of graft function over 7 years. Nine matched pairs were from adult donors (mean age, 40 years; range, 23-60 years) and six from pediatric donors (mean age, 11 years; range, 4-15 years). All recipients had comparable immunosuppression with cyclosporine A, prednisolone, and azathioprine and comparable numbers of acute rejection, cytomegalovirus reactivation, and antihypertensive therapy. Mean age of pediatric and adult recipients at transplantation was 5 years (range, 1-9 years) and 38 years (range, 25-60 years), respectively. RESULTS: The calculated glomerular filtration rate (GFR) corrected to body surface area was not different in adult and pediatric recipients. Initial absolute GFR was significantly lower in pediatric recipients (27 mL/ min; range, 17-38 mL/min) than in adult recipients (54 mL/min; range, 25-74 mL/min) (P <0.05) and remained lower in the following years. Initially, pediatric donor kidneys transplanted into pediatric recipients showed a lower absolute GFR than those transplanted into adults, however, approaching the GFR in adult recipients later. Adult donor kidneys transplanted into pediatric recipients showed a persistently lower absolute GFR in children compared with those transplanted into adult recipients. CONCLUSIONS: The authors conclude that adult donor kidneys in pediatric recipients decrease GFR in the early stages and lack an increase in GFR with growth of the child.  相似文献   
20.
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