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   3380篇
  免费   186篇
  国内免费   27篇
耳鼻咽喉   15篇
儿科学   122篇
妇产科学   108篇
基础医学   452篇
口腔科学   56篇
临床医学   282篇
内科学   944篇
皮肤病学   53篇
神经病学   318篇
特种医学   85篇
外科学   253篇
综合类   6篇
一般理论   1篇
预防医学   158篇
眼科学   13篇
药学   317篇
中国医学   21篇
肿瘤学   389篇
  2023年   19篇
  2022年   69篇
  2021年   92篇
  2020年   50篇
  2019年   70篇
  2018年   93篇
  2017年   71篇
  2016年   82篇
  2015年   100篇
  2014年   126篇
  2013年   163篇
  2012年   251篇
  2011年   273篇
  2010年   126篇
  2009年   152篇
  2008年   252篇
  2007年   223篇
  2006年   193篇
  2005年   219篇
  2004年   218篇
  2003年   155篇
  2002年   156篇
  2001年   37篇
  2000年   41篇
  1999年   39篇
  1998年   34篇
  1997年   33篇
  1996年   19篇
  1995年   17篇
  1994年   10篇
  1993年   10篇
  1992年   22篇
  1991年   19篇
  1990年   27篇
  1989年   13篇
  1988年   13篇
  1987年   13篇
  1986年   6篇
  1985年   8篇
  1984年   8篇
  1983年   5篇
  1982年   7篇
  1980年   4篇
  1979年   4篇
  1978年   5篇
  1975年   6篇
  1973年   8篇
  1969年   4篇
  1967年   7篇
  1966年   3篇
排序方式: 共有3593条查询结果,搜索用时 15 毫秒
91.
Cholangiocarcinoma(CCA) is a malignant tumor of the biliary system and includes, according to the anatomical classification, intra hepatic CCA(iCCA),hilar CCA(hCCA) and distal CCA(dCCA). Hilar CCA is the most challenging type in terms of diagnosis, treatment and prognosis. Surgery is the only treatment possibly providing long-term survival, but only few patients are considered resectable at the time of diagnosis. In fact, tumor's extension to segmentary or subsegmentary biliary ducts, along with large lymph node involvement or intrahepatic metastases, precludes the surgical approach. To achieve R0 margins is mandatory for the disease-free survival and overall survival. In case of unresectable locally advanced hCCA, radiochemotherapy(RCT) as neoadjuvant treatment demonstrated to be a therapeutic option before either hepatic resection or liver transplantation. Before liver surgery, RCT is believed to enhance the R0 margins rate. For patients meeting the Mayo Clinic criteria, RCT prior to orthotopic liver transplant(OLT) has proved to produce acceptable 5-years survivals. In this review, we analyze the current role of neoadjuvant RCT before resection as well as before OLT.  相似文献   
92.
Cotard's syndrome is a neuropsychiatric disease characterized by a variety of nihilistic delusions, commonly associated with several psychotic and major affective disorders, and neurological diseases, including stroke, dementia, and mental retardation. A 39-year-old male with mental retardation developed Cotard's syndrome, following an important episode of fear. During admission to our neurological unit, the patient underwent an accurate assessment, including neuroradiological, clinical, and neuropsychological examinations. At the psychiatric evaluation, he presented nihilistic delusions, in which he negated the existence of his body parts and the existence of his family members. The neuropsychological assessment ruled out other possible causes of misidentification, including the post-traumatic stress disorder. Thus, since also organic causes of Cotard's syndrome were excluded, the correlation between fear and the syndrome has been postulated and the patient opportunely treated, using a multidisciplinary approach. Our case suggests that in predisposed individuals negative emotions, including fear, may lead to delusional syndromes.  相似文献   
93.
94.
Takotsubo Cardiomyopathy is characterized by a reversible systolic left ventricular apical ballooning. A new pattern of dyskinesia in the absence of angiographic evidence of coronary artery stenosis has been indicated like a variant of takotsubo cardiomiopathy: mid-ventricular akinesis with preservation of apical and basal contractilities revealed at echocardiograms and ventriculographies. We report the case of a 65 years old patient with this pattern, reverted in 4 weeks.  相似文献   
95.
Natural killer (NK) cells provide a major defence against human cytomegalovirus (HCMV) infection through the interaction of their surface receptors, including the activating and inhibitory killer immunoglobulin‐like receptors (KIRs), and human leucocyte antigen (HLA) class I molecules. Also γ marker (GM) allotypes, able to influence the NK antibody‐dependent cell‐mediated cytotoxicity, appear to be involved in the immunological control of virus infections, including HCMV. In some cases, their contribution requires epistatic interaction with other genes of the immune system, such as HLA. In the present report, with the aim of gaining insight into the immune mechanisms controlling HCMV, we have studied the possible associations among humoral and NK responses, and HCMV infections. In a previous study we assessed whether the KIR and HLA repertoire might influence the risk of developing symptomatic (n = 60) or asymptomatic (n = 60) disease after primary HCMV infection in the immunocompetent host. In the present study, the immunocompetent patients with primary symptomatic HCMV infection were genotyped for GM3/17 and GM23 allotypes, along with the 60 participants with a previous asymptomatic infection as controls. Notwithstanding the presence of missing data record, advanced missing data recovery techniques were able to show that individuals carrying the GM23 allotypes, both homozygous and heterozygous, GM17/17, HLA‐C2 and Bw4T KIR‐ligand groups are associated with the risk of developing symptomatic infection. Our findings on the role of both cellular and humoral immunity in the control of HCMV infection should be of value in guiding efforts to reduce HCMV‐associated health complications in the elderly, including immunosenescence, and in transplantation.  相似文献   
96.
Minimally invasive treatment for small renal cell carcinoma (RCC) can be necessary in selected patients and, anyway, is desirable. In situ ablation techniques, including RFA, have been developed. The aim of this study is to evaluate the feasibility, safety and short-term local effectiveness of percutaneous US-guided RFA in a small series, as well as mid-term patient outcome. Thirteen patients with a total of 18 tumors (17 small lesions, 35 mm in size or less, and a larger one, 75 mm in size) underwent 19 RFA sessions. Seven patients had a solitary kidney, and three suffered from VHL disease, too. We treated four lesions in a patient with a bilateral tumor. In another patient, three lesions were ablated. Seventeen tumors were RCC; one was a metastasis from lung cancer. Eight lesions were parenchymal, six exophytic, two parenchymal/exophytic, one parenchymal/central and one central. A monopolar RF system with multitined expandable electrode needles was used. The 35-mm lesion underwent two sessions; the 75-mm lesion was treated with transcatheter arterial embolization before RFA. Tumors with complete loss of contrast enhancement at short-term CT (or MR) were considered successfully treated. Percutaneous US-guided RFA was always feasible without major complications. The success rate after a single treatment in tumors less than 35 mm in size was 88.2% (15/17) and rose to 94.1% (16/17) after the second treatment of the largest lesion. After a mean 14-month follow-up, no successfully treated lesions recurred locally. Only the patient with metastasis from lung cancer died from disease progression in a further location, while all other patients are alive, with renal function still sufficient to avoid dialysis. US guidance allows an easy and safe percutaneous approach for RFA of small non-parahilar RCC. The treatment is locally effective and can be proposed as a minimally invasive therapy for patients with contraindications to surgery or to those expressing an informed consent. Based on the results of this study and of the literature, mid-term results on the clinical usefulness are very encouraging.Presented at ECR 2003.  相似文献   
97.
To test a prediction of our previous computational model of cortico‐hippocampal interaction (Gluck and Myers [1993, 2001]) for characterizing individual differences in category learning, we studied young healthy subjects using an fMRI‐adapted category‐learning task that has two phases, an initial phase in which associations are learned through trial‐and‐error feedback followed by a generalization phase in which previously learned rules can be applied to novel associations (Myers et al. [2003]). As expected by our model, we found a negative correlation between learning‐related hippocampal responses and accuracy during transfer, demonstrating that hippocampal adaptation during learning is associated with better behavioral scores during transfer generalization. In addition, we found an inverse relationship between Blood Oxygenation Level Dependent (BOLD) activity in the striatum and that in the hippocampal formation and the orbitofrontal cortex during the initial learning phase. Conversely, activity in the dorsolateral prefrontal cortex, orbitofrontal cortex and parietal lobes dominated over that of the hippocampal formation during the generalization phase. These findings provide evidence in support of theories of the neural substrates of category learning which argue that the hippocampal region plays a critical role during learning for appropriately encoding and representing newly learned information so that that this learning can be successfully applied and generalized to subsequent novel task demands. Hum Brain Mapp 35:3122–3131, 2014. © 2013 Wiley Periodicals, Inc .  相似文献   
98.
Broad‐spectrum muscarinic receptor antagonists have represented the first available treatment for different movement disorders such as dystonia. However, the specificity of these drugs and their mechanism of action is not entirely clear. We performed a systematic analysis of the effects of anticholinergic drugs on short‐ and long‐term plasticity recorded from striatal medium spiny neurons from DYT1 dystonia knock‐in (Tor1a+/Δgag) mice heterozygous for ΔE‐torsinA and their controls (Tor1a+/+ mice). Antagonists were chosen that had previously been proposed to be selective for muscarinic receptor subtypes and included pirenzepine, trihexyphenydil, biperiden, orphenadrine, and a novel selective M1 antagonist, VU0255035. Tor1a+/Δgag mice exhibited a significant impairment of corticostriatal synaptic plasticity. Anticholinergics had no significant effects on intrinsic membrane properties and on short‐term plasticity of striatal neurons. However, they exhibited a differential ability to restore the corticostriatal plasticity deficits. A complete rescue of both long‐term depression (LTD) and synaptic depotentiation (SD) was obtained by applying the M1‐preferring antagonists pirenzepine and trihexyphenidyl as well as VU0255035. Conversely, the nonselective antagonist orphenadrine produced only a partial rescue of synaptic plasticity, whereas biperiden and ethopropazine failed to restore plasticity. The selectivity for M1 receptors was further demonstrated by their ability to counteract the M1‐dependent potentiation of N‐methyl‐d ‐aspartate (NMDA) current recorded from striatal neurons. Our study demonstrates that selective M1 muscarinic receptor antagonism offsets synaptic plasticity deficits in the striatum of mice with the DYT1 dystonia mutation, providing a potential mechanistic rationale for the development of improved antimuscarinic therapies for this movement disorder. © 2014 International Parkinson and Movement Disorder Society  相似文献   
99.
100.
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