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   6052篇
  免费   261篇
  国内免费   102篇
耳鼻咽喉   63篇
儿科学   72篇
妇产科学   172篇
基础医学   450篇
口腔科学   198篇
临床医学   442篇
内科学   2016篇
皮肤病学   84篇
神经病学   403篇
特种医学   219篇
外科学   1304篇
综合类   28篇
现状与发展   1篇
一般理论   2篇
预防医学   225篇
眼科学   131篇
药学   241篇
中国医学   3篇
肿瘤学   361篇
  2024年   6篇
  2023年   70篇
  2022年   150篇
  2021年   276篇
  2020年   163篇
  2019年   218篇
  2018年   263篇
  2017年   155篇
  2016年   191篇
  2015年   178篇
  2014年   293篇
  2013年   337篇
  2012年   509篇
  2011年   549篇
  2010年   353篇
  2009年   314篇
  2008年   449篇
  2007年   470篇
  2006年   432篇
  2005年   312篇
  2004年   263篇
  2003年   181篇
  2002年   147篇
  2001年   33篇
  2000年   8篇
  1999年   12篇
  1998年   25篇
  1997年   13篇
  1996年   8篇
  1995年   7篇
  1994年   14篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1985年   1篇
  1984年   2篇
  1979年   1篇
  1975年   2篇
  1969年   1篇
排序方式: 共有6415条查询结果,搜索用时 0 毫秒
71.
OBJECTIVES: Hepatic steatosis is a common feature of chronic hepatitis C. The purpose of this study was to determine factors related to the presence of steatosis and to define the role of steatosis in the response to antiviral treatment in chronic hepatitis C patients. METHODS: We retrospectively analysed all patients with chronic hepatitis C treated in a 5 year period in our department. Patients were included in the study only if a pretreatment liver biopsy specimen was available for evaluation. All patients treated either with interferon in combination with ribavirin, or with pegylated interferon in combination with ribavirin were included irrespectively of their response (early, end of treatment and/or sustained) to antiviral therapy. RESULTS: A total of 116 patients with chronic hepatitis C were included in the study with a mean age of 45.5 +/- 14.1 years. Steatosis was present in 52 patients (44.8%). On univariate analysis age, P = 0.04 and body mass index > or = 25, P = 0.004 were correlated with the presence of steatosis and on multivariate analysis only body mass index > or = 25, P = 0.032. Advanced fibrosis was not found associated with steatosis. Sixty patients out of 116 (51.7%) had sustained virological response (SVR). In particular 42 out of 64 patients with no steatosis (65.6%) had SVR compared to 20 out of 52 patients (38.4%) with any degree of steatosis (P = 0.009). Patients with genotype 2 or 3 had a more favourable outcome compared to patients with 1 or 4 genotypes, 63.2% vs 49.2%, P = 0.032. Also increased age (P = 0.0001), gamma glutamyltransferase (GGT) (P = 0.029), no history of intravenous drugs use (P = 0.001) and advanced fibrosis on pretreatment biopsy (P = 0.046) were correlated with treatment failure. On multivariate analysis significant independent association with SVR was found with the presence of steatosis on pretreatment biopsy (P = 0.004), increased GGT (P = 0.005) and genotype (P = 0.017). CONCLUSION: Steatosis in the liver biopsy performed before the beginning of antiviral treatment was found to be associated only to the body mass index of the patients and to be a strong independent factor for treatment failure.  相似文献   
72.
73.
Colistin has been revived, in the era of extensively drug-resistant (XDR) Gram-negative infections, as the last-resort treatment in critically ill patients. Recent studies focusing on the optimal dosing strategy of colistin have demonstrated the necessity of a loading dose at treatment initiation (D. Plachouras, M. Karvanen, L. E. Friberg, E. Papadomichelakis, A. Antoniadou, I. Tsangaris, I. Karaiskos, G. Poulakou, F. Kontopidou, A. Armaganidis, O. Cars, and H. Giamarellou, Antimicrob Agents Chemother 53:3430–3436, 2009, http://dx.doi.org/10.1128/AAC.01361-08; A. F. Mohamed, I. Karaiskos, D. Plachouras, M. Karvanen, K. Pontikis, B. Jansson, E. Papadomichelakis, A. Antoniadou, H. Giamarellou, A. Armaganidis, O. Cars, and L. E. Friberg, Antimicrob Agents Chemother 56:4241– 4249, 2012, http://dx.doi.org/10.1128/AAC.06426-11; S. M. Garonzik, J. Li, V. Thamlikitkul, D. L. Paterson, S. Shoham, J. Jacob, F. P. Silveira, A. Forrest, and R. L. Nation, Antimicrob Agents Chemother 55:3284–3294, 2011, http://dx.doi.org/10.1128/AAC.01733-10). In 19 critically ill patients with suspected or microbiologically documented infections caused by XDR Gram-negative strains, a loading dose of 9 MU colistin methanesulfonate (CMS) (∼270 mg colistin base activity) was administered with a maintenance dose of 4.5 MU every 12 h, commenced after 24 h. Patients on renal replacement were excluded. CMS infusion was given over 30 min or 1 h. Repeated blood sampling was performed after the loading dose and after the 5th or 6th dose. Colistin concentrations and measured CMS, determined after hydrolization to colistin and including the partially sulfomethylated derivatives, were determined with a liquid chromatography-tandem mass spectrometry assay. Population pharmacokinetic analysis was conducted in NONMEM with the new data combined with data from previous studies. Measured colistimethate concentrations were described by 4 compartments for distribution and removal of sulfomethyl groups, while colistin disposition followed a 1-compartment model. The average observed maximum colistin A plus B concentration was 2.65 mg/liter after the loading dose (maximum time was 8 h). A significantly higher availability of the measured A and B forms of colistimethate and colistin explained the higher-than-expected concentrations in the present study compared to those in previous studies. Creatinine clearance was a time-varying covariate of colistimethate clearance. The incidence of acute renal injury was 20%.  相似文献   
74.
75.
76.
77.
The percutaneous closure of ostium secundum atrial septal defects (ASD) is a well-established procedure. Currently available devices and delivery systems are designed to be used via the femoral venous route. However, an alternative approach needs to be considered in cases of congenital or acquired caval obstruction. We describe a successful transjugular closure of a moderate sized secundum ASD with the Cocoon Septal Occluder in a 37-year-old symptomatic woman with inferior vena cava (IVC) thrombosis, using a novel deployment technique to overcome difficulties, namely maintaining stable sheath position in the left atrium. Percutaneous closure of secundum ASDs via the transjugular approach is safe, feasible and effective and can be a reasonable alternative to surgical closure in patients with failed femoral venous access and not anatomically complex atrial septal defects.  相似文献   
78.
79.
BACKGROUNDHepatectomy with inflow occlusion results in ischemia-reperfusion injury; however, pharmacological preconditioning can prevent such injury and optimize the postoperative recovery of hepatectomized patients. The normal inflammatory response after a hepatectomy involves increased expression of metalloproteinases, which may signal pathologic hepatic tissue reformation. AIMTo investigate the effect of desflurane preconditioning on these inflammatory indices in patients with inflow occlusion undergoing hepatectomy.METHODSThis is a single-center, prospective, randomized controlled trial conducted at the 4th Department of Surgery of the Medical School of Aristotle University of Thessaloniki, between August 2016 and December 2017. Forty-six patients were randomized to either the desflurane treatment group for pharmacological preconditioning (by replacement of propofol with desflurane, administered 30 min before induction of ischemia) or the control group for standard intravenous propofol. The primary endpoint of expression levels of matrix metalloproteinases and their inhibitors was determined preoperatively and at 30 min posthepatic reperfusion. The secondary endpoints of neutrophil infiltration, coagulation profile, activity of antithrombin III (AT III), protein C (PC), protein S and biochemical markers of liver function were determined for 5 d postoperatively and compared between the groups.RESULTSThe desflurane treatment group showed significantly increased levels of tissue inhibitor of metalloproteinases 1 and 2, significantly decreased levels of matrix metalloproteinases 2 and 9, decreased neutrophil infiltration, and less profound changes in the coagulation profile.  During the 5-d postoperative period, all patients showed significantly decreased activity of AT III, PC and protein S (vs baseline values, P < 0.05). The activity of AT III and PC differed significantly between the two groups from postoperative day 1 to postoperative day 5 (P < 0.05), showing a moderate drop in activity of AT III and PC in the desflurane treatment group and a dramatic drop in the control group. Compared to the control group, the desflurane treatment group also had significantly lower international normalized ratio values on all postoperative days (P < 0.005) and lower serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase values on postoperative days 2 and 3 (P < 0.05).   Total length of stay was significantly less in the desflurane group (P = 0.009).CONCLUSIONDesflurane preconditioning can lessen the inflammatory response related to ischemia-reperfusion injury and may shorten length of hospitalization.  相似文献   
80.
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