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   3095篇
  免费   225篇
  国内免费   7篇
耳鼻咽喉   76篇
儿科学   61篇
妇产科学   78篇
基础医学   435篇
口腔科学   44篇
临床医学   333篇
内科学   562篇
皮肤病学   58篇
神经病学   273篇
特种医学   128篇
外科学   607篇
综合类   13篇
预防医学   179篇
眼科学   67篇
药学   189篇
肿瘤学   224篇
  2021年   59篇
  2020年   31篇
  2019年   41篇
  2018年   72篇
  2017年   43篇
  2016年   67篇
  2015年   84篇
  2014年   101篇
  2013年   126篇
  2012年   173篇
  2011年   202篇
  2010年   126篇
  2009年   115篇
  2008年   147篇
  2007年   135篇
  2006年   168篇
  2005年   147篇
  2004年   112篇
  2003年   128篇
  2002年   104篇
  2001年   68篇
  2000年   105篇
  1999年   95篇
  1998年   44篇
  1997年   18篇
  1996年   28篇
  1995年   18篇
  1994年   19篇
  1993年   24篇
  1992年   47篇
  1991年   44篇
  1990年   47篇
  1989年   31篇
  1988年   50篇
  1987年   35篇
  1986年   38篇
  1985年   26篇
  1984年   23篇
  1983年   17篇
  1982年   22篇
  1980年   18篇
  1979年   18篇
  1978年   18篇
  1977年   17篇
  1975年   17篇
  1974年   16篇
  1973年   22篇
  1972年   16篇
  1970年   16篇
  1968年   18篇
排序方式: 共有3327条查询结果,搜索用时 31 毫秒
81.
82.
83.
OBJECTIVE: To identify the somatostatin receptor-expressing cells in rheumatoid synovium using a recently developed antiserum directed against the somatostatin receptor subtype 2A (sst2A). METHODS: We carried out immunohistochemical studies of synovial biopsies from 7 patients with rheumatoid arthritis (RA) and one non-RA patient, using a rabbit polyclonal antiserum directed against sst2A and monoclonal antibodies directed against phenotypic markers. RESULTS: SSt2A was expressed by the endothelial cells of the synovial venules but also by a subset of synovial macrophages. CONCLUSION: The identification of somatostatin receptors on macrophages, which are thought to be important effector cells in RA, may offer mechanistic insights into the potential therapeutic effect of somatostatin (analogs) in RA.  相似文献   
84.
Glucose tolerance and B cell function were assessed in 30 consecutive chronic alcoholic patients without overt diabetes mellitus. Plasma glucose, insulin, and C peptide concentrations were measured during an oral glucose tolerance test. All patients underwent a liver biopsy and an exocrine pancreatic function test (Lundh test). Compared with the controls, the three groups of alcoholic patients (those with histologically normal livers, n = 12; those with steatosis, n = 10; and those with cirrhosis, n = 8) all had a two-fold increase in plasma concentrations of insulin as well as C peptide in the fasting state, despite normal fasting levels of glucose. After oral glucose all groups of patients had elevated plasma levels of glucose, insulin, and C peptide compared with the controls. The C peptide/insulin ratio was similar to that in the controls in all groups of alcoholics. Patients with decreased exocrine pancreatic function (n = 7) had a significantly lower insulin and C peptide response to glucose than the patients with normal exocrine pancreatic function. It is concluded that (1) chronic alcoholics even with histologically normal livers have endogenous insulin resistance, and (2) associated damage to the exocrine pancreas is more common than previously recognized and decompensation of B cell function could be demonstrated in patients with decreased exocrine pancreatic secretion.  相似文献   
85.
We compared EUCAST and CLSI antifungal susceptibility testing (AFST) methods for triazoles and amphotericin B against 124 clinical Mucorales isolates. The EUCAST method yielded MIC values 1- to 3-fold dilutions higher than those of the CLSI method for amphotericin B. The essential agreements between the two methods for triazoles were high, i.e., 99.1% (voriconazole), 98.3% (isavuconazole), and 87% (posaconazole), whereas it was significantly lower for amphotericin B (66.1%). Strategies for harmonization of the two methods for Mucorales AFST are warranted.  相似文献   
86.
Cognitive Therapy and Research - The Self Regulatory Executive Function (S-REF) model implicates maladaptive metacognitive beliefs and processes in the predisposition and/or maintenance of positive...  相似文献   
87.
Singh  Simron  Dey  Chris  Kennecke  Hagen  Kocha  Walter  Maroun  Jean  Metrakos  Peter  Mukhtar  Tariq  Pasieka  Janice  Rayson  Daniel  Rowsell  Corwyn  Sideris  Lucas  Wong  Ralph  Law  Calvin 《Annals of surgical oncology》2015,22(8):2685-2699
Annals of Surgical Oncology - Pancreatic neuroendocrine tumors (pNETs) are rare heterogeneous tumors that have been steadily increasing in both incidence and prevalence during the past few decades....  相似文献   
88.
OBJECTIVES: The histologic criterion of >20 eosinophils per high power field (hpf) is presently believed to establish the diagnosis of idiopathic eosinophilic esophagitis (IEE). This is based on data that the number of intraepithelial eosinophils in gastroesophageal reflux disease (GERD) is less than 20/hpf. This study tests this belief. METHODS: Pathology records were searched for patients who had an eosinophil count >20/hpf in an esophageal biopsy. This patient population was biased toward adults with GERD who had routine multilevel biopsies of the esophagus. The clinical, radiological, and manometric data and biopsies were studied. RESULTS: Forty patients out of a total of 3,648 reports examined had an eosinophil count >20/hpf in squamous epithelium of an esophageal biopsy. Analysis of these 40 cases indicated that 6 (15%) patients had IEE, 2 (5%) had coincident IEE and GERD, 28 (70%) had GERD, and 2 (5%) each had achalasia and diverticulum. There was no significant difference among these groups in terms of maximum eosinophil number, biopsy levels with >20 esoinophils/hpf, presence of eosinophilic microabscesses, involvement of surface layers by eosinophils, and severity of basal cell hyperplasia and dilated intercellular spaces. CONCLUSION: All histologic features presently ascribed to IEE can occur in other esophageal diseases, notably GERD. As such, the finding of intraepithelial eosinophilia in any number is not specific for IEE. When a patient with GERD has an esophageal biopsy with an eosinophil count >20/hpf, it does not mean that the patient has IEE.  相似文献   
89.
BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement can result in patient-valve mismatch and attenuated left ventricular remodeling. Using CarboMedics mechanical valves, we examined if the supraannular Top Hat prosthesis provided a size advantage over the intraannular valve. METHODS: Seventeen patients with aortic stenosis and aortic root < or = 23 mm were randomized to receive a CarboMedics supraannular Top Hat valve (n = 7) or an intraannular valve (n = 10). Doppler echocardiography was performed preoperatively, and after three months. RESULTS: There was no difference in aortic annulus size, but mean prosthesis size was significantly larger in the Top Hat group than in the intraannular group (25.00 mm versus 21.60 mm); the mean size improvement for Top Hat patients was 3.14 mm. After three months, all patients had excellent functional improvement and low transvalvular pressure gradients, with slightly higher effective valve opening area in the Top Hat group. CONCLUSION: The supraannular Top Hat valve provides an advantage of one to two sizes over the intraannular valve, and improves the effective valve opening area. Both valves offer favorable hemodynamic performance and functional improvement.  相似文献   
90.
Great amounts of omics data are generated in aging research, but their diverse and partly complementary nature requires integrative analysis approaches for investigating aging processes and connections to age-related diseases. To establish a broader picture of the genetic and epigenetic landscape of human aging we performed a large-scale meta-analysis of 6600 human genes by combining 35 datasets that cover aging hallmarks, longevity, changes in DNA methylation and gene expression, and different age-related diseases. To identify biological relationships between aging-associated genes we incorporated them into a protein interaction network and characterized their network neighborhoods. In particular, we computed a comprehensive landscape of more than 1000 human aging clusters, network regions where genes are highly connected and where gene products commonly participate in similar processes. In addition to clusters that capture known aging processes such as nutrient-sensing and mTOR signaling, we present a number of clusters with a putative functional role in linking different aging processes as promising candidates for follow-up studies. To enable their detailed exploration, all datasets and aging clusters are made freely available via an interactive website (https://gemex.eurac.edu/bioinf/age/).  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