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   1746篇
  免费   70篇
  国内免费   8篇
耳鼻咽喉   75篇
儿科学   71篇
妇产科学   84篇
基础医学   191篇
口腔科学   18篇
临床医学   102篇
内科学   420篇
皮肤病学   17篇
神经病学   236篇
特种医学   56篇
外科学   208篇
综合类   5篇
一般理论   2篇
预防医学   79篇
眼科学   23篇
药学   119篇
肿瘤学   118篇
  2023年   12篇
  2022年   8篇
  2021年   43篇
  2020年   23篇
  2019年   40篇
  2018年   37篇
  2017年   21篇
  2016年   24篇
  2015年   33篇
  2014年   51篇
  2013年   72篇
  2012年   106篇
  2011年   143篇
  2010年   68篇
  2009年   52篇
  2008年   107篇
  2007年   148篇
  2006年   123篇
  2005年   104篇
  2004年   150篇
  2003年   104篇
  2002年   95篇
  2001年   6篇
  2000年   8篇
  1999年   9篇
  1998年   14篇
  1997年   5篇
  1996年   11篇
  1995年   5篇
  1994年   8篇
  1993年   6篇
  1992年   7篇
  1991年   10篇
  1990年   13篇
  1989年   5篇
  1988年   5篇
  1987年   9篇
  1986年   6篇
  1984年   5篇
  1982年   6篇
  1981年   7篇
  1976年   5篇
  1974年   5篇
  1973年   7篇
  1963年   4篇
  1960年   4篇
  1948年   4篇
  1931年   5篇
  1930年   6篇
  1912年   3篇
排序方式: 共有1824条查询结果,搜索用时 15 毫秒
1.
Ohne Zusammenfassung Aus dem Cabinet der Klinik des Professors Mirzeewsky. Der psychiatrischen Gesellschaft in St. Petersburg am 28. Januar 1884 mitgetheilt.  相似文献   
2.
3.
Taurolidine (TRD) has antimicrobial and anti-inflammatory properties. However, the anti-inflammatory effects of TRD in inflammatory bowel diseases (IBD) have not been investigated. Here, we have analyzed the toxicity of TRD after oral long-term application in mice and examined the impact of oral TRD in a dextran sulfate sodium (DSS) model of experimental colitis. Female C57/BL6 mice received TRD in various concentrations (0.1% to 0.4%) for 60 days. Toxicity was evaluated by use of a disease activity index (DAI) and histological examination of major metabolic organs. Furthermore, the impact of 0.2% TRD on a chronic DSS colitis was examined by daily DAI, histological crypt damage score (CDS), bacterial translocation into mesenteric lymph nodes (MLN), and colonic expression of tumor necrosis factor (TNF) alpha, transforming growth factor (TGF) beta, interleukin (IL)-1beta, IL-6, cytochrome oxidase (COX)-2, and monocyte chemotactic protein (MCP)-1 by real-time polymerase chain reaction (PCR). Oral TRD administration for 60 days was well tolerated by the animals and did not show any toxic effects in terms of DAI and histological changes. TRD treatment of DSS colitis led to increased survival of 100%, compared to 33% in the untreated colitis group (p < or = .005). Clinical amelioration was mirrored by significantly reduced DAI and CDS in the TRD treated colitis. Colonic cytokine expression and bacterial translocation into MLN showed no differences between both groups. We thus report for the first time that oral application of TRD results in amelioration of an experimental IBD model. We hypothesize direct intraluminal antimicrobial effects of TRD as well as anti-inflammatory effects during the acute phase of DSS colitis.  相似文献   
4.
Abstract: Background: The laryngeal mask airway (LMA) can be used in general anaesthesia without neuromuscular block. The laryngeal tube (LT) is a new airway device with similar airway features as LMA. LT is provided with a distal cuff to prevent regurgitation. In this study we compared the LMA and LT concerning patient and user aspects. Methods: Sixty patients with ASA (American Society of Anestesiologists) score 1–2 scheduled for minor surgery were randomized to be ventilated either through LMA or LT. After insertion, the number of insertion attempts, and “positioning” and “airway-assessment” was evaluated. The patients reported on “sore throat” after 30 and 60 minutes and the day after anaesthesia. Results: Gender and mean age were equal in both groups. The first insertion attempt was successful in 25 of 28 patients randomised to LMA and in 23 of 27 patients randomised to LT. LMA was evaluated to be easier in “positioning” whereas no difference in “sore throat” was reported. Conclusion: We found no difference between the LMA and the LT in terms user and patient friendliness and safety.  相似文献   
5.
Regional cerebral blood flow (rCBF) was measured with high resolution brain dedicated single photon emission computer tomography (SPECT) and [99mTc]-d,l-hexamethyl-propylene-amine-oxime (HMPAO) in 25 patients with probable Alzheimer's disease and in 25 control subjects, selected according to rigorous inclusion and exclusion criteria. The aim was to analyse the topography of rCBF deficits in individual patients. In the group of patients with Alzheimer's disease as a whole, global CBF was reduced, but a factorial analysis of variance did not show disproportionate reduction of rCBF in any brain region. A parametric analysis of the rCBF data in individual patients was carried out with reference to normal values for internal rCBF ratios and to 13 different abnormal rCBF patterns. These theoretical patterns were predefined by showing significant hypoperfusion in at least one, or in any relevant combination of two, three, or four, of four major brain regions (a left and right frontal and a left and right posterior region). All patients with Alzheimer's disease and none of the control subjects had an abnormal rCBF pattern. Eleven of the 13 different patterns were seen in the patients. Frontal changes were seen in 19 (76%) of the patients, more often than previously reported. No single Alzheimer's disease pattern could be derived from our data. The number of regions with hypoperfusion, but not the presence of frontal changes, correlated significantly with the duration of disease. It is concluded that a clinical diagnosis of probable Alzheimer's disease is associated with heterogeneous patterns of rCBF deficits as measured with SPECT and [99mTc]-d,l-HMPAO. This heterogeneity may reflect different stages of the disease or cognitive subtypes and help explain published discrepancies concerning the topography of hypoperfusion in Alzheimer's disease. An analysis of individual rCBF data may add important information in the investigation of diseases with heterogeneous effects on the brain.  相似文献   
6.
PURPOSE: To investigate the morphological effects of acute overdistension in the structure of the extracellular matrix of the bladder wall in rats. MATERIALS AND METHODS: The bladders of a group of 6 male Wistar rats were transurethrally overdistended for 3 hours. Another identical group (the control group) was only submitted to a sham operation. Specimens from the bladder dome were analyzed with light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). RESULTS: LM--The control group bladders had a 4 to 5 layer urothelium, a lamina propria, and a smooth muscle layer with longitudinal and transversal fibers. The overdistended bladders presented an intense interstitial infiltrate in the lamina propria, and a less intense infiltrate among the smooth muscle fibers. TEM--The cells of the overdistended bladders had a significant amount of vacuoles, unlike the control bladders, where such vacuoles were scarce or absent. SEM--A delicate three-dimensional mesh of collagen fibrils was observed in the lamina propria of the bladder walls from the control group. Whilst for the control group this mesh consisted of distinct geometric structures, with mostly circular cellular spaces surrounded by the fibrils, the overdistended group showed evidence of distortion of the mesh, with flattened and elongated cellular spaces. CONCLUSIONS: Acute bladder overdistension induces structural modifications, altering the arrangement and interaction of collagen fibrils, as well as incipient tissue damage as edema in the lamina propria and smooth muscle layers.  相似文献   
7.
The aim of this international guideline on dementia was to present a peer-reviewed evidence-based statement for the guidance of practice for clinical neurologists, geriatricians, psychiatrists, and other specialist physicians responsible for the care of patients with dementia. It covers major aspects of diagnostic evaluation and treatment, with particular emphasis on the type of patient often referred to the specialist physician. The main focus is Alzheimer's disease, but many of the recommendations apply to dementia disorders in general. The task force working group considered and classified evidence from original research reports, meta-analysis, and systematic reviews, published before January 2006. The evidence was classified and consensus recommendations graded according to the EFNS guidance. Where there was a lack of evidence, but clear consensus, good practice points were provided. The recommendations for clinical diagnosis, blood tests, neuroimaging, electroencephalography (EEG), cerebrospinal fluid (CSF) analysis, genetic testing, tissue biopsy, disclosure of diagnosis, treatment of Alzheimer's disease, and counselling and support for caregivers were all revised when compared with the previous EFNS guideline. New recommendations were added for the treatment of vascular dementia, Parkinson's disease dementia, and dementia with Lewy bodies, for monitoring treatment, for treatment of behavioural and psychological symptoms in dementia, and for legal issues. The specialist physician plays an important role together with primary care physicians in the multidisciplinary dementia teams, which have been established throughout Europe. This guideline may contribute to the definition of the role of the specialist physician in providing dementia health care.  相似文献   
8.
INTRODUCTION: Aseptic loosening is a result of the chronic inflammatory reaction in periprosthetic tissues. Its intensity depends on the implants construction material and reactivity of the host's tissues. The aim of the study was the evaluation of the acute phase proteins in various periods following total hip replacement and comparison between acute phase response observed in patients with well-functioning implants and with aseptic loosening. MATERIAL: The study group consisted of 97 patients following THR due to the hip osteoarthritis. Patients of Group I were evaluated before the surgery and 6 months after primary THR. Group II consisted of patients 3-4 years after primary THR. Group consisted of patients with aseptic loosening. Patients of all groups were divided according to the implant type (cemente/uncemented). METHODS: Concentrations of evaluated acute phase proteins: C-reactive protein (CRP), transferrin (Tf) and alpha-glycoprotein were assessed using immunoelectrophoresis. RESULTS: In vast majority of patients (71-95%) following THR had present w3 variant of AGP which should be negative in physiological conditions. The average concentrations of AGP and AGP-RC were higher in patients following cemented THR. CONCLUSIONS: Implantation of the endoprosthesis raises a chronic inflammatory reaction expressed by changes in the profiles of acute phase proteins. This process is more visible in patients following cemented THR. The profiles of the acute phase proteins in patients with aseptic loosening were not different than those observed in patients with well-functioning implants, what makes them useless as a diagnostic tool for loosening. This lack of differences may be caused by adaptation of the generalised response to long lasting process of aseptic loosening  相似文献   
9.
10.
Summary:  Members of the cytohesin protein family, a group of guanine nucleotide exchange factors for adenosine diphosphate ribosylation factor (ARF) guanosine triphosphatases, have recently emerged as important regulators of signal transduction in vertebrate and invertebrate biology. These proteins share a modular domain structure, comprising carboxy-terminal membrane recruitment elements, a Sec7 homology effector domain, and an amino-terminal coiled-coil domain that serve as a platform for their integration into larger signaling complexes. Although these proteins have a highly similar overall build, their individual biological functions appear to be at least partly specific. Cytohesin-1 had been identified as a regulator of β2 integrin inside-out regulation in immune cells and was subsequently shown to be involved in mitogen-associated protein kinase signaling in tumor cell proliferation as well as in T-helper cell activation and differentiation. Cytohesin-3, which had been discovered to be strongly associated with T-cell anergy, was very recently described as an essential component of insulin signal transduction in Drosophila and in human and murine liver cells. Future work will aim to dissect the mechanistic details of the modes of action of the cytohesins as well as to define the precise roles of these versatile proteins in vertebrates at the genetic level.  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